The Standard Electrical Dictionary
by T. O'Conor Sloane · English · Gutenberg #26535 · 1,375,981 chars · public domain (US)
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Title: The Standard Electrical Dictionary
Author: T. O'Conor Sloane
Release date: September 5, 2008 [eBook #26535]
Most recently updated: March 13, 2025
Language: English
Other information and formats: www.gutenberg.org/ebooks/26535
Credits: Produced by Don Kostuch
*** START OF THE PROJECT GUTENBERG EBOOK THE STANDARD ELECTRICAL DICTIONARY ***
[Transcriber's Notes]
Obvious spelling errors have been corrected. I have not reconciled the
variety of spellings of names and other words. Obvious factual errors,
typographical errors, discoveries made after 1892, and contemporary
(2008) theories and use of words are noted in the text within square
brackets. I have not researched and checked every assertion by the
author.
This book was published 5 years before discovery of the electron. See
the labored and completely inaccurate explanations of aurora and
"energy, atomic". The author and his contemporaries were like fifteenth
century sailors. They had a good idea of their latitude and direction
(Ampere, Kirkoff, Maxwell, Gauss, Faraday, Edison, …), but only the
vaguest notion of their longitude (nuclear structure, electrons, ions).
Altitude (special relativity, quantum theory) was not even imagined.
Some relevant dates:
Franklin's Kite--1752
Faraday's Law of Induction--1831
Maxwell's Equations--1861
Edison's Phonograph--1877
Edison's light bulb--1879
Edison's first DC power station--1882
Michelson-Morley experiment disproving ether--1887
Hertz demonstrates radio waves--1888
Westinghouse first AC power station--1891
This book--1892
Discovery of the electron--1897
Marconi radio signals cross the English Channel--1897
First Vacuum Tube--1904
Special Relativity, photo-electric effect explained with photons--1905
General Relativity: space-time dilation and curvature--1915
Confirmation of general relativity's prediction of the deflection
of starlight by the Sun--1919
Discovery of the proton--1920
Quantum theory--1926
Discovery of neutron--1932
First transistor--1947
Soviet satellite Luna measures solar wind--1959
Edward M. Purcell explains magnetism with special relativity--1963
Purcell's explanation of magnetism as a result of Lorentz contraction of
space along the direction of a current is a welcome relief from the
convoluted descriptions in this book.
Mathematical notation is rendered using "programming" notation.
^ Power--Exponential; A^3 means "A cubed"
* Multiply
/ Divide
+ Add
- Subtract
( ) Precedence--Perform before enclosing expression
2E6 Scientific Notation (2,000,000)
A
---------------------
4.452 X 10^12 X t
is rendered as
A / ( 4.452E12 * t )
Where the rendering of a mathematical expression is in doubt, an image
of the original text is included.
Here are some definitions absent from the text.
Foucault currents.
Eddy currents.
inspissate
To thicken, as by evaporation.
riband
Ribbon.
sapotaceous
Order Sapotace[ae] of trees and shrubs, including the star apple, the
Lucuma, or natural marmalade tree, the gutta-percha tree (Isonandra),
and the India mahwa, as well as the sapodilla, or sapota, after which
the order is named.
Don Kostuch, MS, Electrical Engineering.
[End Transcriber's notes.]
WORKS OF
T. O'CONOR SLOANE, A.M., E.M., Ph.D.
ARITHMETIC OF ELECTRICITY
A MANUAL OF ELECTRICAL CALCULATIONS
BY ARITHMETICAL METHODS.
Third Edition. Illustrated. $1.00.
It is very useful to that class of readers to whom Algebra is a
comparatively unknown quantity, and will meet its wants
admirably.--Electrical World.
ELECTRICITY SIMPLIFIED.
A POPULAR TREATMENT OF THE SUBJECT.
Illustrated. $1. 00.
We especially recommend it to those who would like to acquire a popular
idea of the subject.--Electric Age.
ELECTRIC TOY MAKING.
FOR AMATEURS.
INCLUDING BATTERIES, MAGNETS, MOTORS, MISCELLANEOUS TOYS,
AND DYNAMO CONSTRUCTION.
Fully Illustrated. $1.00.
THE STANDARD ELECTRICAL DICTIONARY.
A POPULAR DICTIONARY OF WORDS AND TERMS
USED IN THE PRACTICE OF ELECTRICAL ENGINEERING.
BY
T. O'CONOR SLOANE, A.M., E.M., Ph.D.
NEW YORK
GEORGE D. HURST
PUBLISHER
Copyright 1892
by
NORMAN W. HENLEY & CO.
PREFACE
The purpose of this work is to present the public with a concise and
practical book of reference, which it is believed will be appreciated in
this age of electricity. The science has expanded so much that the
limits of what may be termed strictly a dictionary of the present day
would a few years ago have sufficed for an encyclopedia. It follows that
an encyclopedia of electricity would be a work of great size. Yet a
dictionary with adequate definitions, and kept within the closest limits
by the statement of synonyms, and by the consigning of all the
innumerable cross-references to a concise index will be far more than a
mere dictionary in the ordinary sense of the term.
Duplication of matter is to be avoided. This makes many definitions
appear short. Yet, by the assistance of the reader's own general
knowledge, and by referring to the very complete index, almost any
subject can be found treated in all its aspects. There are exceptions to
this statement. So much has been done in the way of mechanical detail,
so many inventions in telegraphy and other branches have sprung into
prominence only to disappear again, or to be modified out of
recognition, that to embody descriptions of many ingenious and
complicated apparatus has been absolutely impossible for want of space.
A word as to the use of the book and the system of its construction may
be given here. Each title or subject is defined once in the text. Where
a title is synonymous with one or more others the definition is only
given under one title, and the others appear at the foot of the article
as synonyms. It may be that the reader is seeking the definition of one
of these synonyms. If so a reference to the index shows him at once what
page contains the information sought for. The use of an index in a work,
necessarily of an encyclopedic form, will be appreciated by all users of
this book.
vi PREFACE.
Where a title embraces several words, all orders of the words will be
cited in the index. To make the operation of finding references easy
this rule has been carried out very fully.
It is customary to regard electricity as a growing science. It is
unquestionably such, but the multiplication of terms and words is now
not nearly so rapid as it has been, and the time for the compiling of a
work of this character seems most propitious. It is hoped that the
public will indulgently appreciate the labor it has entailed on all
concerned in its production.
SYMBOLS AND ABBREVIATIONS.
adj. Adjective.
v. Verb.
q.v. "Which see.'
/ A mark of division, as A/B, meaning "A divided by B."
./. The same as above.
[Transcriber's note: / will be substituted for this divide symbol.]
= A mark of equality, meaning "is equal to."
X A mark of multiplication, meaning "multiplied by."
[Transcriber's note: * will be substituted for this divide symbol.]
Fractional exponents indicate the roots expressed by their denominators
and the powers expressed by their numerators. Thus, A^1/2 means the
"square root of A;" A^1/3 means the "cube root of A;" B^3/2 means the
"square root of the cube or third power of B."
The use of powers of ten, as 10^10, 10^11, as multipliers, will be found
explained at length in the definition "Ten, Powers of."
vii STANDARD ELECTRICAL DICTIONARY
A.
Abbreviation for anode, employed in text relating to
electro-therapeutics. It is sometimes written An.
Abscissa.
In a system of plane co-ordinates (see Co-ordinates) the
distance of any point from the axis of ordinates measured parallel to
the axis of abscissas.
In the cut the abscissa of the point a is the line or distance a c.
Fig. 1. AXES OF CO-ORDINATES.
Absolute. adj.
In quantities it may be defined as referring to fixed units of quantity,
and it is opposed to "relative," which merely refers to the relation of
several things to each other. Thus the relative resistance of one wire
may be n times that of another; its absolute resistance might be 5 ohms,
when the absolute resistance of the second wire would be 5/n ohms. A
galvanometer gives absolute readings if it is graduated to read directly
amperes or volts; if not so graduated, it may by "calibration" q. v. be
made to do practically the same thing.
8 STANDARD ELECTRICAL DICTIONARY.
Absolute Measurement.
Measurement based upon the centimeter, gram, and second. (See
Centimeter-Gram-Second System.)
Absolute Temperature.
Temperature reckoned from absolute zero (see "Zero, Absolute"). It is
obtained by adding for the centigrade scale 273, and for the Fahrenheit
scale 459, to the degree readings of the regular scale.
Absorption, Electric.
A property of the static charge. When a Leyden jar is being charged it
dilates a little and the capacity increases, so that it can take a
little more charge for a given potential difference existing between its
two coatings. This phenomenon occurs with other static condensers,
varying in degree with the dielectric. With shellac, paraffin, sulphur
and resin, for instance, the absorption is very slight; with
gutta-percha, stearine, and glass, the absorption is relatively great.
The term is due to Faraday. Iceland spar seems almost or quite destitute
of electric absorption.
A. C. C.
Symbol of or abbreviation for "anodic closure contraction" q. v.
Acceleration.
The rate of change of velocity. If of increase of velocity it is
positive; if of decrease, it is negative. It can only be brought about
by the exercise of force and is used as the measure of or as determining
the unit of force. It is equal to velocity (L/T) imparted, divided by
time (T); its dimensions therefore are L/(T^2). The c. g. s. unit of
acceleration is one centimeter in one second.
[Transcriber's note: The unit of acceleration is "centimeters per second
per second."]
Accumulator.
(a) A term sometimes applied to the secondary or storage battery. (See
Battery, Secondary.)
(b) See Accumulator, Electrostatic
(c) See Accumulator, Water Dropping.
(d) See Wheel, Barlow's
Accumulator, Electrostatic.
Two conducting surfaces oppositely placed, and separated by a
dielectric and arranged for the opposite charging of the two surfaces,
constitute an accumulator, sometimes termed a condenser. As this
arrangement introduces the element of a bound and of a binding charge,
the electrostatic capacity of such is greater than that of either or of
both of its component surfaces. The thinner the dielectric which
separates the conducting surfaces, and the larger the surfaces the
greater is the capacity; or the less will be the potential difference
which a given charge will establish between its two coatings. The nature
of the dielectric also determines its capacity. (See Capacity, Specific
Inductive.)
9 STANDARD ELECTRICAL DICTIONARY.
Fig. 2. SIR WILLIAM THOMSON'S WATER-DROPPING ACCUMULATOR.
Accumulator, Water Dropping.
This is also known as Sir William Thomson's Water-Gravity Electric
Machine. It is an apparatus for converting the potential energy of
falling water drops, due to gravity, into electric energy. Referring to
the illustration, G represents a bifurcated water pipe whose two faucets
are adjusted to permit a series of drops to fall from each. C and F are
two metallic tubes connected by a conductor; E and D are the same. Two
Leyden jars, A and B, have their inner coatings represented by strong
sulphuric acid, connected each to its own pair of cylinders, B to D and
E, and A to F and C. The outer coatings are connected to earth, as is
also the water supply. One of the jars, say A, is charged interiorily
with positive electricity. This charge, C and F, share with it, being in
electric contact therewith. Just before the drops break off from the jet
leading into C, they are inductively charged with negative electricity,
the positive going to earth. Thus a series of negatively excited drops
fall into the metal tube D, with its interior funnel or drop arrester,
charging it, the Leyden jar B, and the tube E with negative electricity.
This excitation causes the other stream of drops to work in the converse
way, raising the positive potential of F and C and A, thus causing the
left-hand drops to acquire a higher potential. This again raises the
potential of the right-hand drops, so that a constant accumulating
action is kept up. The outer coatings of the Leyden jars are connected
to earth to make it possible to raise the potential of their inner
coatings. In each case the drops are drawn by gravity into contact with
objects similarly excited in opposition to the electric repulsion. This
overcoming of the electric repulsion is the work done by gravity, and
which results in the development of electric energy.
10 STANDARD ELECTRICAL DICTIONARY.
Acidometer.
A hydrometer or areometer used to determine the specific gravity of
acid. They are employed in running storage batteries, to determine when
the charging is completed. (See Areometer.)
Aclinic Line.
A terrestrial element; the locus on the earth's surface of no
inclination of the magnetic needle; the magnetic equator. (See Magnetic
Elements.)
Acoustic Telegraphy.
The system of sound-reading in telegraphy, universally used in the Morse
system. The direct stroke of the armature of the electro-magnet and its
"back stroke" disclose to the ear the long and short strokes, dots and
lines, and long and short spaces as produced by the dispatcher of the
message. In the Morse system a special magnet and armature is used to
produce the sound called the "sounder;" in other systems, e. g.,
Steinheil's and Bright's apparatus, bells are used. (See Alphabets,
Telegraphic.)
Acoutemeter.
A Hughes audiometer or sonometer applied to determining the quality of a
person's hearing (See Hughes' Induction Balance,--Audiometer). The
central coil by means of a tuning fork and microphone with battery
receives a rapidly varying current tending to induce currents in the
other two coils. Telephones are put in circuit with the latter and pick
up sound from them. The telephones are applied to the ears of the person
whose hearing is to be tested. By sliding the outer coils back and forth
the intensity of induction and consequent loudness of the sounds in the
telephones is varied. The position when the sounds grow so faint as to
be no longer audible, gives the degree of delicacy of the person's
hearing. By using a single telephone the same apparatus affords a means
of testing the relative capacity of the right and left ears.
11 STANDARD ELECTRICAL DICTIONARY.
Actinic Rays.
The rays of light at the violet end of the spectrum; also the invisible
rays beyond such end, or the ether waves of short periods which most
strongly induce chemical change.
Actinism.
The power possessed by ether waves of inducing chemical change, either
of decomposition or of combination. The violet and ultra-violet end of
the spectrum of white light, generally speaking, represent the most
highly actinic rays.
Actinometer, Electric.
Properly an apparatus for measuring the intensity of light by its action
upon the resistance of selenium. A current produced by fixed
electro-motive force passing through the selenium affects a galvanometer
more or less according to the intensity of the light. It is more
properly an electric photometer. The term has also been applied to a
combination of a thermo-electric pile and galvanometer, the light
falling on the pile affecting the motions of the galvanometer.
Action, Local.
(a) The wasteful oxydation of the zinc in a galvanic battery due to
local impurities and variations in the composition of the zinc. These
act to constitute local galvanic couples which cause the zinc to
dissolve or oxydize, without any useful result. Amalgamation of the zinc
prevents local action. Chemically pure zinc is also exempt from local
action, and can be used in an acid battery without amalgamation. (See
Amalgamation.)
(b) The same term has been employed to indicate the eddy or foucault
currents in dynamo electric machines. (Sec Current, Foucault.)
Activity.
The rate of doing work; the work done per second by any expenditure of
energy. The activity of a horse-power is 550 foot lbs. per second, or
746 volt-coulombs per second. The practical electric unit is the
volt-ampere, often called the watt. (Sec Energy, Electric.)
Adapter.
A screw coupling to engage with a different sized screw on each end; one
of the uses is to connect incandescent lamps to gas-fixtures.
A. D. C.
Abbreviation for Anodic Duration Contraction, q. v.; a term in
electro-therapeutics.
Adherence, Electro-magnetic.
The adherence between surfaces of iron due to elcctro-magnetic
attraction. It has been applied to the driving-wheels of an engine and
rail, whose grip is increased by such action. In one method a deep
groove was cut around the wheel which was wound with a magnetizing coil.
Thus one rim becomes a north and the other a south pole, and the rail
completing the circuit acts as the armature. Such an arrangement
prevents a wheel from sliding. Electro-magnetic adherence has also been
employed to drive friction gear wheels. In one arrangement the two
wheels are surrounded by a magnetizing coil, under whose induction each
attracts the other, developing high adherence between their peripheries.
12 STANDARD ELECTRICAL DICTIONARY.
Fig. 3. ELECTRO-MAGNETIC CAR WHEEL.
Fig. 4. ELECTRO-MAGNETIC FRICTION GEAR.
Admiralty Rule of Heating.
The British Admiralty specifications for the permissible heating of
dynamos. It holds that at the end of a run of six hours no part of the
dynamo under trial shall show a rise of temperature greater than 11º C.
(20º F.) above the temperature of the air surrounding it. This is
thought to be a very stringent and unnecessarily high requirement.
Aerial Conductor.
An electric conductor carried from housetops, poles, or otherwise so as
to be suspended in the air, as distinguished from an underground or
submarine conductor.
Affinity.
The attraction of atoms and in some cases perhaps of molecules for each
other by the force of chemical attraction. When the affinity is allowed
to act or is carried out, a chemical change, as distinguished from a
physical or mechanical change, ensues. Thus if sulphur and iron are each
finely powdered and are mixed the change and mixture are mechanical. If
slightly heated the sulphur will melt, which is a physical change. If
heated to redness the iron will combine with the sulphur forming a new
substance, ferric sulphide, of new properties, and especially
characterized by unvarying and invariable ratios of sulphur to iron.
Such change is a chemical one, is due to chemical affinity, is due to a
combination of the atoms, and the product is a chemical compound.
13 STANDARD ELECTRICAL DICTIONARY.
Agir Motor.
The Anderson and Girdlestone motor. The term "agir" is made up from the
first portions of each name.
Agonic Line.
The locus of points on the earth's surface where the magnetic needle
points to the true north; an imaginary line determined by connecting
points on the earth's surface where the needle lies in the true
geographical meridian. Such a line at present, starting from the north
pole goes through the west of Hudson's Bay, leaves the east coast of
America near Philadelphia, passes along the eastern West Indies, cuts
off the eastern projection of Brazil and goes through the South Atlantic
to the south pole. Thence it passes through the west of Australia, the
Indian Ocean, Arabia, the Caspian sea, Russia and the White sea to the
North Pole. It crosses the equator at 70° W. and 55° E. approximately.
(See Magnetic Elements.)
Synonym--Agone.
[Transcriber's note: The file Earth_Declination_1590_1990.gif provided
by the U.S. Geological Survey (http://www.usgs.gov) is an animation of
the declination of the entire earth.]
Air.
Air is a dielectric whose specific inductive capacity at atmosphere
pressure is taken as 1. It is practically of exactly the same
composition in all places and hence can be taken as a standard. When dry
it has high resistance, between that of caoutchouc and dry paper.
Dampness increases its conductivity.
It is a mixture of oxygen and nitrogen, with a little carbonic acid gas
and other impurities. Its essential composition is:
Oxygen: (by weight) 23.14 (by volume) 21
Nitrogen: 76.86 79
The specific inductive capacity varies for different pressures thus:
Approximate vacuum (.001 mm., .0004 inch) 0.94 (Ayrton)
" " ( 5 mm. , .2 inches ) 0.9985 (Ayrton)
0.99941 (Boltzman.)
The specific gravity of air under standard conditions 15.5° C (60° F.)
and 760 mm. barometric pressure (30 inches) is taken as unity as a
standard for gases.
[Transcriber's note: Argon accounts for 0.9340%. It was discovered in
1894, two years after this book.]
Air-Blast.
(a) In the Thomson-Houston dynamo an air-blast is used to blow away the
arc-producing spark liable to form between the brushes and commutator.
It is the invention of Prof. Elihu Thomson. The air is supplied by a
positive action rotary blower connected to the main shaft, and driven
thereby. The wearing of the commutator by destructive sparking is thus
prevented.
A drum H H is rotated, being mounted on the axis X of the dynamo. As it
rotates the three vanes are thrown out against the irregular shaped
periphery of the outer case T T. The arrow shows the direction of
rotation. The air is thus sent out by the apertures a a. O is the
oil-cup.
(b) The air-blast has also been used by Prof. Thomson in experiments
with high frequency currents of high potential. By directing a blast of
air against a spark discharge between ball terminals of an alternating
current, the nature of the current was changed and it became capable of
producing most extraordinary effects by induction.
14 STANDARD ELECTRICAL DICTIONARY.
Fig. 5. AIR BLOWER FOR THOMSON'S DYNAMO.
Air Condenser.
A static condenser whose dielectric is air. The capacity of an air
condenser in farads is equal to
A / ( 4.452E12 * t )
in which A is the area of one sheet or sum of the areas of one set of
connected sheets in square inches and t is the thickness of the layer of
air separating them.
A convenient construction given by Ayrton consists in a pile of glass
plates P separated by little bits of glass F of known thickness, three
for each piece. Tin-foil T is pasted on both sides of each piece of
glass and the two coatings are connected. The tin-foil on each second
plate is smaller in area than that on the others. The plates are
connected in two sets, each set comprising every second plate. For A in
the formula the area of the set of smaller sheets of tin-foil is taken.
By this construction it will be seen that the glass does not act as the
dielectric, but only as a plane surface for attachment of the tin-foil.
Posts E E keep all in position. One set of sheets connects with the
binding post A, the other with B.
The capacity of any condenser with a dielectric of specific inductive
capacity i is given by the formula:
( i *A^1 ) / ( 4.452E12 * t1 )
The air condenser is used for determining the value of i for different
dielectrics.
Fig. 6. AIR CONDENSER.
15 STANDARD ELECTRICAL DICTIONARY.
Air Gaps.
In a dynamo or motor the space intervening between the poles of the
field magnet and the armature. They should be of as small thickness, and
of as extended area as possible. Their effect is to increase the
magnetic reluctance of the circuit, thereby exacting the expenditure of
more energy upon the field. They also, by crowding back the potential
difference of the two limbs, increase the leakage of lines of force from
limb to limb of the magnet.
Air Line Wire.
In telegraphy the portion of the line wire which is strung on poles and
carried through the air.
Air Pump, Heated.
It has been proposed to heat portions of a mercurial air pump to secure
more perfect vacua, or to hasten the action. Heating expands the air and
thus produces the above effects.
16 STANDARD ELECTRICAL DICTIONARY.
Air Pump, Mercurial.
An air pump operated by mercury. The mercury acts virtually as the
piston, and the actuating force is the weight of the column of mercury,
which must exceed thirty inches in height. There are many types.
Mercurial air pumps are largely used for exhausting incandescent lamp
chambers. (See Geissler Air Pump,--Sprengel Air Pump.)
Air Pumps, Short Fall.
A mercurial air pump in which the fall of mercury or the height of the
active column is comparatively small. It is effected by using several
columns, one acting after the other. A height of ten inches for each
column suffices in some forms. Enough columns must be used in succession
to make up an aggregate height exceeding 30 inches.
Fig. 7. BURGLAR ALARM SWITCH OR CIRCUIT BREAKER.
Fig. 8. BURGLAR ALARM SWITCH OR CIRCUIT BREAKER.
Alarm, Burglar.
A system of circuits with alarm bell extending over a house or
apartments designed to give notice of the opening of a window or door.
As adjuncts to the system the treads of the stairs are sometimes
arranged to ring the bell, by completing a circuit when trod on. Door
mats are also arranged to close circuits in like manner.
17 STANDARD ELECTRICAL DICTIONARY.
For doors and windows switches are provided which are open as long as
the door or window is closed, but which, on being released by opening
the door or windows, automatically close the circuit. The circuit
includes an alarm bell and battery, and the latter begins to ring and
continues until stopped, either by the closing of the door or by a
switch being turned. The connections are sometimes so contrived that the
reclosing of the door or window will not stop the bell from ringing.
The cuts show various switches for attachment to doors and windows. It
will be seen that they normally keep the circuit closed, and that it is
only open when pressure, as from a closed door, is brought upon them. In
the case of a door a usual place for them is upon the jamb on the hinge
side, where they are set into the wood, with the striking pin
projecting, so that as the door is closed the pin is pressed in, thus
breaking the circuit.
Sometimes the connections are arranged so as to switch on the electric
lights if the house is entered. Special annunciators showing where the
house has been entered are a part of the system. A clock which turns the
alarm on and off at predetermined hours is also sometimes used.
The circuits may be carried to a central station or police station. One
form of burglar alarm device is the Yale lock switch. This is a contact
attached to a Yale lock which will be closed if the wrong key is used,
completing a circuit and ringing a bell.
Fig. 9. BURGLAR ALARM SWITCH OR CIRCUIT BREAKER.
Alarm, Electric.
An appliance for calling attention, generally by
ringing a bell. It is used to notify of water-level in boilers or tanks,
of entrance of a house, or of other things as desired. It is evident
that any number of alarms could be contrived.
18 STANDARD ELECTRICAL DICTIONARY.
Alarm, Fire and Heat.
An alarm for giving notice of the existence of a conflagration. Such are
sometimes operated by a compound bar thermostat (see Thermostat), which
on a given elevation of temperature closes a circuit and rings an
electric bell. Sometimes the expansion of a column of mercury when
heated is used. This, by coming in contact with one or two platinum
points, completes a circuit, and rings the bell.
The identical apparatus may be used in living rooms, greenhouses.
factories and elsewhere, to give an alarm when the temperature rises or
falls beyond predetermined limits.
Alarm, Overflow.
An alarm to indicate an overflow of water has been suggested on the
lines of a contact completed by water, or of the elements of a battery
which would be made active by water. Thus two sheets of metal might be
separated by bibulous paper charged with salt. If these sheets were
terminals of a circuit including a bell and battery, when water reached
them the circuit would be closed and the bell would ring. It was also
proposed to use one copper and one zinc sheet so as to constitute a
battery in itself, to be thrown into action by moisture. These contacts
or inactive batteries could be distributed where water from an overflow
would be most likely to reach them.
Alarm, Water Level.
An alarm operated by a change of water level in a tank or boiler. By a
float a contact is made as it rises with the water. Another float may be
arranged to fall and close a contact as the level falls. The closing of
the contacts rings an electric bell to notify the attendant in charge.
Alcohol, Electrical Rectification of.
A current of electricity passed through impure alcohol between zinc
electrodes is found to improve its quality. This it does by decomposing
the water present. The nascent hydrogen combines with the aldehydes,
converting them into alcohols while the oxygen combines with the zinc
electrode.
Alignment.
The placing in or occupying of the same straight line. The bearings of a
shaft in dynamos, engines, and other machinery have to be in accurate
alignment.
Allotropy.
The power of existing in several modifications possessed by some
substances, notably by chemical elements. Instances of the allotropic
state are found in carbon which exists as charcoal, as graphite
(plumbago or black lead), and as the diamond. All three are the same
elemental substance, although differing in every physical and electrical
property.
19 STANDARD ELECTRICAL DICTIONARY.
Alloy.
A mixture, produced almost universally by fusion, of two or more metals.
Sometimes alloys seem to be chemical compounds, as shown by their having
generally a melting point lower than the average of those of their
constituents. An alloy of a metal with mercury is termed an amalgam. An
important application in electricity is the use of fusible alloys for
fire alarms or for safety fuses. German silver is also of importance for
resistance coils, and palladium alloys are used for unmagnetizable
watches. An alloy of wrought iron with manganese is almost
unmagnetizable, and has been proposed for use in ship building to avoid
errors of the compass.
Alloys or what are practically such can be deposited by electrolysis in
the electro- plater's bath. We give the composition of some alloys
interesting to the electrician.
Solder: Lead 1 part Tin 2 parts
" " " 1 "
" " " 2 "
German Silver: Copper, 2 parts; Nickel, 1 part;
Zinc, 1 part (used for resistances).
Platinum, Silver Alloys: Platinum, 1 part;
silver, 2 parts (used for resistances.)
Palladium alloys for watch springs. (See Palladium.)
Alphabet, Telegraphic.
The combinations of sounds, of dots and dashes marked on paper, of
right-hand and left-hand deflections of a needle, of bells of different
notes, or of other symbols by which a fixed combination is expressed for
each character of the alphabet, for numerals, and for punctuation. While
the code is designed for telegraphic uses it can be used not only for
the conveyance of signals and messages by the electrical telegraphs, but
also by any semaphoric or visual system, as by flashes of light,
movements of a flag or even of the arms of the person signalling.
In the English and continental needle telegraphy in which the message is
transmitted by the movements of an index normally vertical, but
oscillating to one side or the other under the influence of the current,
the latter being controlled by the transmitter of the message, the left
hand swings of the needle are interpreted as dots, the right hand as
dashes.
This system enables one alphabet to be translated into the other, or
virtually one alphabet answers for both Morse and needle transmitters.
There are two principal telegraphic alphabets, the American Morse and
the International codes. They are very similar, their essential
distinction being that spaces are used in the American code, while they
are excluded from the International code.
In the American Morse system the message is now universally received by
sound. (See Sounder--Sound Reading.)
20 STANDARD ELECTRICAL DICTIONARY.
The two codes or telegraphic alphabets are given here.
THE INTERNATIONAL ALPHABET.
Parenthesis, - . - - . -
Understand, ... - .
I don't understand, ..-- ....--..
Wait, .-. . .
Erase, ... ... ...
Call signal, -.-.-.-
End of message, .-.-.-.
Cleared out all right, .-..-..-.
A .- L .-.. W .--
B -... M -- X -..-
C -.-. N -. Y -.--
D -.. O --- Z --..
E . P .--.
F ..-. Q --.- Ch ----
G --. R .-. Ä .-.-
H .... S ... Ö ---.
I .. T - Ü ..--
J .--- U ..- É ..-..
K -.- V ...- Ñ --.--
NUMERALS
1 .---- 4 ....- 8 ---..
2 ..--- 5 ..... 9 ----.
3 ...-- 6 -.... 0 -----
7 --...
[Transcriber's note: The original image of the dot/dash pattern is somewhat
ambiguous. Since there may be differences from contemporary specifications,
the original image is included.]
[Image of page 20: THE INTERNATIONAL ALPHABET.]
21 STANDARD ELECTRICAL DICTIONARY.
PUNCTUATION, ETC.,
Period (.) ... ...
Comma (,) .-.-.-
Query(?) ..--..
Exclamation (!) --..--
Apostrophe (') .----.
Hyphen (-) -....-
Fresh paragraph, .-.-..
Inverted commas, -..-.
THE AMERICAN ALPHABET.
A .- L ----(Continuous) W .--
B -... M -- X .-..
C ..s. N -. Y ..s..
D -.. O .s. Z ….
E . P .....
F .-. Q ..-. Ch ----
G --. R .s.. Ä .-.-
H .... S ... Ö ---.
I .. T - Ü ..--
J - . - . U ..- É ..-..
K -.- V ...- Ñ --.--
NUMERALS
1 .--. 4 ....- 8 -....
2 ..-.. 5 --- 9 -..-
3 ...-. 6 ... ... 0 -----(Continuous)
7 --..
[Transcriber's Note: The "s" in the American Code indicates a "space". I
leave the following to the reader's imagination. See the original
image.]
Comma (,)
Semicolon (;)
Colon (:)
Colon Dash (:~)
Period (.)
Interrogation (?)
Exclamation (!)
Dash (-)
Hyphen (-)
Pound Sterling (£)
Shilling Mark ( )
[Image of page 21: THE AMERICAN ALPHABET.]
22 STANDARD ELECTRICAL DICTIONARY.
[Transcriber's Note: I leave these to the reader's imagination. See the
following original image.]
Dollars ($)
Decimal Point (.)
Cents (c)
Paragraph ()
Pence (d.)
Fractional Mark (--)
Capitalized Letter
Italics or Underline
Colon followed by Quotation :"
Parenthesis ( )
Brackets [ ]
Quotation Marks " "
Quotation within a Quotation " ' ' "
[Image of page 22: THE AMERICAN ALPHABET.]
The principal differences in the two codes are the use of spaces in the
American code, such being excluded from the International code. This
affects the letters C, R, Y, & Z.
The following diagram, due to Commandant Perian, enables the letter
corresponding to an International code sign to be rapidly found with the
exception of R.
<- dot start dash ->
/ \
E T
/ \ / \
I A N M
/ \ / \ / \ / \
S U R W D K G O
/ \ / \ / \ / \ / \ / \ / \ / \
H V F U L A P J B X C Y Z Q Ô CH
Fig. 10. Diagram for translating the Morse Alphabet.
In order to find what letter corresponds to a given sign, starting from
the top of the diagram, each line is traced down to a bifurcation,
taking the right hand line of each bifurcation for a dash, and the left
hand line for a dot, and stopping when the dots and dashes are used up.
Thus, for example,
the signal -.- - leads us to the letter d,
the signal - - - - to the letter j and so on.
23 STANDARD ELECTRICAL DICTIONARY.
Alternating. adj.
Term descriptive of a current changing periodically in
direction. (See Current, Alternating.)
Synonyms--Oscillatory--periodic--undulatory--harmonic.
Alternating Current Arc.
The arc produced by the alternating current. It presents several
peculiarities. With an insufficient number of alternations per second it
goes out. As the carbons wear away equally it is adopted for such lamps
as the Jablochkoff candle, (see Candle, Jablochkoff). As no crater is
formed the light is disseminated equally both up and down. For this
reason to get full downward illumination a reflector is recommended.
Alternating Current System.
A system of electric distribution employing the alternating current. For
transmission in the open air or in conduits a high potential circuit is
used, from 1,000 to 10,000 volts being maintained at the central
station. Two leads unconnected at the end lead from the station. Where
current is desired a converter or transformer (see Converter) is placed,
whose primary is connected to the two leads bridging the interval
between them. From the secondary the house leads are taken with an
initial potential in some cases of 50 volts. The converters are thus all
placed in parallel. By law or insurance rules the converters are
generally kept outside of buildings. Where no secondary current is taken
from the converters very little primary current passes them on account
of their counter-electromotive force. As more secondary current is taken
the primary increases and this accommodation of one to the other is one
of the interesting and valuable features. Street lamps are sometimes
connected in series. Each lamp in such case is in parallel with a small
coil with iron core. While the lamp is intact little current passes
through the coil. If the lamp is broken, then the converter impedes the
current by its spurious resistance, q. v., just enough to represent and
replace the resistance of the extinguished and broken lamp filament.
(See Meter, Alternating Current; Motor, Alternating Current.)
Alternation.
The change in direction of a current. The number of such changes is
expressed as number of alternations; thus a current may have a frequency
of 500 or 20,000 alternations per second.
[Transcriber's note: One alternation per second is now called one hertz.]
Alternation, Complete.
A double alternation; a change from one direction
to the other and back again to the original phase. A symbol derived from
its graphic representation by a sine curve is used to indicate it. The
symbol is ~
24 STANDARD ELECTRICAL DICTIONARY.
Alternative Path.
A second path for a current appearing as a disruptive
discharge. Where two paths are offered the discharge, as it is of
alternating or oscillatory type, selects the path of least
self-induction. Thus a thick bar of copper, with no air gap, may be
abandoned by the current in favor of a small iron wire with an air gap,
but which has less self-induction.
The lightning arresters, q. v., for the protection of telegraph offices
are sometimes based on these principles. A path of very high resistance
but of small self-induction is offered between the line and the earth.
This the lightning discharge selects in preference to the instruments
with their iron cores, as the latter are of very high self-induction.
Alternator.
A dynamo electric generator supplying an alternating current. (See
Dynamo, Alternating Current.)
Synonym--Alternating current generator or dynamo.
Alternator, Constant Current.
An alternating current dynamo supplying a current of unvarying virtual
amperage. Alternators of this type are constructed with an armature of
high self-induction. Sometimes fine winding contained in deep peripheral
notches in the core-discs is employed to magnify the self-induction.
Such generators are employed for series lighting, especially
arc-lighting.
Aluminum.
A metal; one of the elements; symbol: Al.
Atomic weight: 27.4. Equivalent: 9.13. Valency: 3.
Specific gravity: 2.6. It is a conductor of electricity.
Relative resistance annealed, (Silver = 1) 1.935
Specific resistance at 0ºC (32°F.) 2.912 microhms
Resistance of a wire at 0ºC (32°F.)
a) 1 foot long, weighing 1 grain, 0.1074 ohms.
b) 1 foot long, 1/1000 inch thick, 17.53 "
c) 1 meter long, weighing 1 gram, 0.0749 "
d) 1 meter long, 1 millimeter thick 0.03710 "
Resistance of a 1-inch cube at 0ºC (32°F.) 1.147 microhms
Electro-chemical equivalent. .0958 (hydrogen == .0105)
25 STANDARD ELECTRICAL DICTIONARY.
Amalgam.
(a) A combination or alloy in which one of the constituents is mercury.
Usually the term is applied to an alloy of a single metal with mercury.
Some metals readily form amalgams; such metals are: Gold, zinc, silver,
lead and others; some, such as platinum and iron, form amalgams only
under exceptional circumstances.
(b) The word is also applied to compositions for application to the
cushions of frictional electric machine in which cases it is often a
misnomer. True amalgams used for this purpose are made as follows:
(a) Tin, 1 part; Zinc, 1 part; Mercury, 2 parts (Kienmayer).
(b) Tin, 2 parts; Zinc, 3 parts.
(c) Tin, 3 parts; Zinc, 5 parts; Mercury, 4 parts.
(d) Zinc, 1 part: Mercury, 4 parts; Mercury, 9 parts. [sic]
The tin, if such is used, (formula a, b and c) is first melted, the zinc
is added in successive portions. The mercury, which must be heated, is
slowly poured into the melted alloy after removal of the latter from the
fire, and the mixture, while making, is constantly stirred. It is kept
stirred or rubbed in a mortar until cold. Sometimes it is poured into
water and kept in constant agitation until cold. It is thus obtained in
a granular condition, and is pounded in a mortar until reduced to
powder. It must be dried and kept in tightly stopped bottles and is
applied to the cushions after they have been greased. It is to be
noticed that it is said that alloy (d) requires no pulverization beyond
constant rubbing in a mortar as it cools. Sometimes the amalgam is
shaken about in a wooden tray with chalk while cooling. The action of
amalgams is not very clearly understood. Some claim that there is a
chemical action, others that they simply act as conductors, others that
they are more highly negative to the glass than the leather of the
cushions.
Graphite or sulphide of tin (mosaic gold) are sometimes used to coat the
cushions; it is these that are sometimes incorrectly called amalgams.
Amalgamation.
The application of mercury to a metal with which it forms an amalgam, or
with which it amalgamates. Battery zincs are amalgamated in two ways. In
the immersion method, the plate is dipped into an acid solution of
mercuric chloride or nitrate. The latter is best. In the direct
application method the plate is first wet all over with dilute acid and
a little mercury is dropped upon it and is rubbed over the surface with
a rag or, what is better, with a piece of galvanized iron. A very little
mercury answers the purpose. The whole surface of the plate should be
left as bright as silver. (See Action, Local.)
Amber.
Amber is a fossil resin, supposed to be a product of the extinct Pinites
Succinifer and other coniferous trees. Most of it is gathered on the
shores of the Baltic between Koenigsberg and Memel. It is also found in
small pieces at Gay Head, Mass., and in New Jersey green sand. It is
found among the prehistoric remains of the Swiss Lake dwellers. When
rubbed with a cloth it becomes excited with negative electricity. The
Greek word for it is electron, which gave the name electricity to the
modern science. Thales of Miletus, 600 B. C., and Theophrastus, about
300 B. C., both mention its electric properties or power of attracting
small objects when rubbed.
26 STANDARD ELECTRICAL DICTIONARY.
Ammeter.
The commercial name for an ampere-meter, an instrument designed
to show by direct reading the number of amperes of current which are
passing through a circuit.
A great variety of ammeters have been invented, based on different
principles. The definitions following this one give some idea of the
lines of construction followed.
Synonym--Ampere meter.
Ammeter, Ayrton's.
A direct reading instrument for measuring current intensity.
A solenoid receives the current. In the axis of the solenoid an iron
tube is suspended by a long spiral spring that passes down within it,
and the upper end of which spring is fastened to the glass top of the
instrument. The tube is provided with proper guides so as to maintain a
vertical position, and is free to rotate. Its upper end carries an
index.
The whole operates as a magnifying device. A slight longitudinal
displacement of the tube causes it to rotate through a considerable
angle by the action of the spring. By properly proportioning the parts,
the angle of displacement of the index is directly proportional to the
current between 15º and 270º angular displacement.
The same instrument is wound for use as a volt-meter.
Its principal fault is its restricted range.
Ammeter, Commutator.
A commutator ammeter is one whose windings consist of separate strands,
each of any desired number of turns, and provided with a commutating
attachment for throwing them into series or into parallel as desired.
The essential condition is that all the wires shall be of equal
resistance and of equal number of turns. Such an instrument can be used
for heavy or light currents. Two sets of graduations are marked on its
scale if it is a calibrated instrument. (See Calibration.) Commutator
volt-meters are constructed on the same principle.
Ammeter, Cunynghame's.
A modification of the Siemens' electro-dynamometer. (See
Electro-dynamometer, Siemens'.) An electro-magnet with very massive core
is excited by the current. As the core is of small reluctance the
strength of the magnet is nearly proportional to the current strength.
Between the poles of the magnet a soft iron armature or induced magnet
is pivoted. It carries a pointer so adjusted that when the axis of the
soft iron magnet is at an angle of about 30º with the line joining the
poles of the electro-magnet the pointer will indicate zero.
The soft iron armature is so massive that the magnetism induced in it is
proportional to the strength of the electro-magnet. Hence the couple
exerted by the electro-magnet on the pivoted armature will be
proportional to the square of the current.
The armature is retained in place by a spiral spring lying in line with
its axis of rotation. The instrument is operated as a zero reading
instrument. The current is passed through it. The needle is deflected;
it is brought back to zero by turning a milled head which twists the
spring. The current will be proportional to the square root of the angle
of displacement of the milled head. A scale with index is provided,
giving directly the square roots of the angle over which the pointer is
moved.
The same instrument is wound for use as a volt-meter.
27 STANDARD ELECTRICAL DICTIONARY.
Ammeter, Eccentric Iron Disc.
This ammeter comprises a cylindrical electro-magnet excited by the
current to be measured. A disc of iron free to rotate is suspended on
pivots below it. A piece is cut off the disc at one part of its
periphery so as to give more metal to one side than to the other. In its
zero position this portion of the disc swings towards the magnet. As the
latter is more and more excited the other or more projecting portion of
the disc turns towards it, being attracted like an armature, and moves
against the force of gravity, the disc rotating. An index attached to
the disc swings over the face of a graduated scale. The disc is so
counterpoised that in its natural position the index points to zero.
Ammeter, Electro-magnetic.
An ammeter depending for its working upon the action of an
electro-magnet, which is excited by the current to be measured.
Ammeter, Gravity.
An ammeter whose hand or index is drawn into the zero position by
gravity, and whose displacement therefrom is produced by the action of
the current to be measured.
Fig. 11. GRAVITY SOLENOID AMMETER.
Ammeter, Magnetic Vane.
A fixed plate of soft iron is placed within a coil. Facing it is a
second disc free to move or swing on an axis. When the field is excited
the two repel each other because like polarity is induced in each, and
the motion of the movable disc indicates the strength of the current.
The same instrument is wound for high resistance and constitutes a
Magnetic Vane Voltmeter.
28 STANDARD ELECTRICAL DICTIONARY.
Ammeter, Magnifying Spring.
A solenoid ammeter in which a spiral spring is used to convert the
longitudinal motion of the armature or movable core into a rotary motion
(see Ammeter, Ayrton's) and magnify the apparent range of motion.
Ammeter, Permanent Magnet.
An ammeter with a magnetic field produced by a permanent magnet.
Ammeter, Solenoid.
An ammeter in which the attraction, when a current is passing through
it, exerted by a hollow coil of wire upon an iron bar or tube in line
with its axis, is utilized to indicate the strength of current. The bar
is drawn into the coil to different extents proportional to the
attraction. As an example see Ammeter, Ayrton's, and cut of Gravity
Ammeter.
Ammeter, Spring.
An ammeter in which the part moved by the current is controlled or
brought to the zero position by a spring.
Ammeter, Steel Yard.
A solenoid ammeter in which the solenoid core is suspended vertically
from the short end of a steel yard fitted with a sliding weight. The
current passes through the solenoid coil and attracts or draws downwards
the coil. A sliding weight is moved in and out on the long steel-yard
arm which is graduated for amperes. In use the weight is slid out until
the arm is in equipose; the divisions give the amperes.
Fig. 12. STEEL YARD AMMETER.
29 STANDARD ELECTRICAL DICTIONARY.
Ammunition Hoist, Electric.
An apparatus for use on ships for hoisting ammunition to the guns by an
electric elevator. The characteristic feature of it is that a constant
motion of the switch or handle is required to keep it in action. If the
operator is shot so as to be incapacitated from taking charge of the
switch, the hoist stops until another is assigned to it.
Amperage.
Current intensity expressed in amperes, as an amperage of ten amperes.
Ampere.
The practical unit of electric current strength. It is the measure of
the current produced by an electro-motive force of one volt through a
resistance of one ohm. In electric quantity it is the rate of one
coulomb per second. It is one-tenth the absolute C. G. S. unit of
current strength. Its best analogy is derived from water. Assuming the
electric current to be represented by a current of water, the pressure,
head, or descent producing such current would be the electro-motive
force. The current might be measured in gallons (or other unit) passed
per second. In the analogy these gallons would be coulombs. But it might
be measured by reference to a standard stream, as for instance, the
stream which would pass through a hole an inch square under a given
head, say six inches of water. This unit is the miner's inch, and is the
exact analogy of the ampere. A current of water may flow at the rate of
so many miner's inches, just as a current of electricity may flow at the
rate of so many amperes. In neither case it will be noted is there any
reference to time. "An ampere per second" is a redundant expression, and
means no more than "an ampere"; an "ampere-second," on the other hand,
is a coulomb. The number of coulombs passed per second gives the amperes
of current.
For value of ampere, see Coulomb.
[Transcriber's note: The SI definition of an ampere: A current in two
straight parallel conductors of infinite length and negligible
cross-section, 1 metre apart in vacuum, would produce a force equal to
2E-7 newton per metre of length.]
Fig. 13. THE MINER'S INCH AS AN ANALOGY FOR THE AMPERE.
30 STANDARD ELECTRICAL DICTIONARY.
Ampere, Arc.
A conductor bent into the arc of a circle, and employed in measuring the
electric current by the electric balance.
Ampere-currents.
The currents assumed to be the cause of magnetism. (See Magnetism,
Ampere's Theory of.)
Ampere-feet.
The product of amperes of current by the length, in feet, of a conductor
passing such current. It may be in empiric calculations of dynamo or
motor construction, but is little used. One ampere-foot is a current of
one ampere passing through one foot length of a conductor, or one-tenth
ampere through ten feet, and so on.
Ampere-hour.
The quantity of electricity passed by a current of one ampere in one
hour. It is used by electric power and lighting companies as the unit of
energy supplied by them, because they maintain a constant potential
difference in their leads, so that only the amperes and hours need
measuring or recording to give the energy, viz. : volt-ampere-hours.
The same unit is applied to batteries to indicate their potential
energy, because they also are assumed to be of constant voltage or
electro-motive force.
Ampere-meters.
The product of amperes of current by the length, in meters, of a
conductor carrying such current. One ampere-meter is a current of one
ampere passing through one meter of a conductor.
The term must not be confused with the identically spelled Ampere-meter,
a synonym for Ammeter.
Ampere-minute.
The quantity of electricity passed by a current of one ampere in one
minute; sixty coulombs.
Ampere Ring.
A conductor forming a ring or circle used in electric balances for
measuring currents. (See Balance, Ampere.)
Ampere-second.
The quantity of electricity passed by a current of one ampere in one
second; the coulomb, q. v.
Amperes, Lost.
In a shunt or compound-wound dynamo, part of the total amperes of
current produced in the armature coils go through the shunt, and hence,
do not appear in the outer circuit. S. P. Thompson has proposed the term
"lost amperes" for this portion of the current.
Ampere's Memoria Technica.
An expression of the effect of a current on a magnetic needle. If we
imagine the observer in the line of the current and facing the magnetic
needle, the current entering by his feet and leaving by his head, the
north pole is deflected to his left.
31 STANDARD ELECTRICAL DICTIONARY.
Ampere-turns.
The amperes of current supplied to a magnet coil multiplied by the
number of turns the current makes in the coil. If the coil is wound two
or three in parallel, the virtual turns by which the amperes are
multiplied are one-half or one-third the actual turns of wire.
Synonym--Ampere Windings.
Ampere-turns, Primary.
The ampere-turns in the primary coil of an induction coil or
transformer.
Ampere-turns, Secondary.
The ampere-turns in the secondary coil of an induction coil or
transformer.
Amplitude of Waves.
Waves are distinguished by length and amplitude. The latter, in the case
of transverse waves, such as those of water and of the ether, correspond
with and measure the height from lowest to highest point, or from valley
to summit of the waves in question. In the case of longitudinal waves,
such as those of the air, due to sounding bodies, the ratio of degree of
rarefaction to degree of condensation existing in the system is the
amplitude. The latter can be graphically represented by a sinuous line,
such as would represent the section of a transverse wave. Ether waves
are produced by heated bodies and by electro-magnetic impulses, as in
the discharge of the Leyden jar.
The amplitude of a wave, other things being equal, is the measure of its
intensity. Thus, the louder a sound the greater is the amplitude of the
system of waves to which it is due. The same applies to ether waves,
whether they are perceived in the electro-magnetic, light, or
heat-giving modification. As the amplitude of ether waves cannot be
accurately known, amplitude is a relative term and is not stated
generally in any absolute unit.
Analogous Pole.
One of the elements of a pyro-electric crystalline substance, such as
tourmaline. When heated, such bodies acquire electrical properties. If
of such crystalline form that they are differently modified at the ends
of their crystalline axis, by hemihedral modifications, the ends may be
differently affected. One end may show positive electricity when the
temperature is rising, and negative when falling. Such end is then
called the analogous pole. The opposite end presents, in such cases, the
opposite phenomena; becoming negative when the temperature is rising,
and becoming positive when it is falling; such end is called the
antilogous pole.
Analysis.
The determination of the elements of a case. It may be chemical, and
consist in finding what a substance consists of; it may be mathematical,
and consist in determining the unknown quantities in a problem; or it
may belong to other branches of science. The term has a very extended
application. Where the constituents are only determined in kind it is
called qualitative analysis; where their quantity or percentage is
ascertained it is called quantitative analysis.
32 STANDARD ELECTRICAL DICTIONARY.
Analysis, Electric.
Chemical analysis by electrolytic methods. (See Electrolytic Analysis.)
Analyzer, Electric.
An apparatus used in investigations on electric ether waves. It consists
of a series of parallel metallic wires. When the electric waves have
been polarized, the analyzer will only permit them to go through it
intact, when the plane of vibration of the waves is parallel to its
wires.
Anelectrics.
(a) Bodies which do not become electrified by friction; a term
introduced by Gilbert, now little used, as all bodies develop
electricity under proper conditions by contact action; the reverse of
idioelectrtics.
(b) Also a conductor of electricity, the reverse of a dielectric, q. v.
(See Conductor.)
It will be seen that Gilbert's anelectrics were, after all, the same as
the modern anelectrics, i.e., conductors.
Anelectrotonus.
A term used in medical electricity or electro-therapeutics to indicate
the deceased functional activity induced in a nerve by the proximity of
the anode of an active electric circuit completed through the nerve. The
converse of Kathelectrotonus.
Angle of Declination.
The angle of error of the magnetic needle or compass, measuring the
extent of its deviation from the meridian in any locality. It is the
angle between the plane of the magnetic axis of a magnetic needle free
to take its natural position, and the geographical meridian, the needle
being counterpoised if necessary, so as to hold an absolutely horizontal
position. The deviation is expressed as being east or west, referring
always to the north pole. (See Magnetic Elements.)
Synonym--Variation of the Compass.
[Transcriber's note: See Agonic Line.]
Angle of the Polar Span.
In a dynamo or motor the angle subtended by the portion of a pole piece
facing the armature, such angle being referred to the centre of the
cross-section of the armature as its centre.
STANDARD ELECTRICAL DICTIONARY. 33
Angular Velocity.
The velocity of a body moving in a circular path, measured with
reference to the angle it passes over in one second multiplied by the
radius and divided by the time. A unit angle is taken (57°.29578 =
57° 17' 44".8 nearly) such that it is subtended by a portion of the
circumference equal in length to the radius. Hence, the circumference,
which is 360°, is equal to 2*PI*unit angle, PI being equal to 3.1416--.
"Unit angular velocity" is such as would in a circle of radius = 1
represent a path = 1, traversed in unit time = 1 second. If the radius
is r and the angle passed over is theta, the distance is proportional to
r*theta; if this distance is traversed in t seconds the angular velocity
is theta / t. The angular velocity, if it is multiplied by r, theta
expressing a distance, will give the linear velocity. The dimensions of
angular velocity are an angle (= arc / radius) / a Time = (L/L)/T =
(T^-1).
The velocity expressed by the rate of an arc of a circle of unit radius,
which arc subtends an angle of 57° 17' 44".8, such arc being traversed
in unit time, is unit angular velocity.
Animal Electricity.
Electricity, notably of high tension, generated in the animal system, in
the Torpedo, Gymnotus and Silurus. The shocks given by these fish are
sometimes very severe. The gymnotus, or electric eel, was elaborately
investigated by Faraday. It has the power of voluntarily effecting this
discharge. There is undoubtedly some electricity in all animals. The
contact of the spinal column of a recently killed frog with the lumbar
muscles produces contraction, showing electric excitement. Currents can
be obtained from nerve and muscle, or from muscle sides and muscle cut
transversely, in each case one thing representing positive and the other
negative elements of a couple.
Angle of Inclination or Dip.
The angle which the magnetic axis of a magnet, which magnet is free to
move in the vertical plane of the magnetic meridian, makes with a
horizontal line intersecting such axis. To observe it a special
instrument, the dipping compass, inclination compass, dipping needle, or
dipping circle, as it is called, is used. (See Elements, Magnetic,
--Dipping Needle,--Compass, Inclination.)
Angle of Lag.
The angle expressing the displacement of the magnetic axis of the
armature core of a dynamo in the direction of its rotation. (See Lag.)
Lag is due to the motion of the armature core.
Angle of Lead.
The angle expressing the displacement in the direction of rotation of
the armature of a dynamo which has to be given the brushes to compensate
for the lag. (See Lag.) This is positive lead. In a motor the brushes
are set the other way, giving a negative angle of lead or angle of
negative lead.
Anion.
The electro-negative element or radical of a molecule, such as oxygen,
chlorine or the radical sulphion. (See Ions.) It is the portion which
goes to the anode, q.v., in electrolytic decomposition.
34 STANDARD ELECTRICAL DICTIONARY.
Anisotropic. (adj.)
Unequal in physical properties, as in conduction and specific inductive
capacity, along various axes or directions. An anisotropic conductor is
one whose conductivity varies according to the direction of the current,
each axis of crystallization in a crystalline body marking a direction
of different conductivity. An anisotropic medium is one varying in like
manner with regard to its specific inductive capacity. In magnetism an
anisotropic substance is one having different susceptibilities to
magnetism in different directions. The term is applicable to other than
electric or magnetic subjects.
Synonym--AEolotropic.
Annealing, Electric.
Annealing by the heat produced by the passage of the electric current
through the body to be annealed. The object is clamped or otherwise
brought into a circuit, and a current strong enough to heat it to
redness, or to the desired temperature is passed through it.
Annunciator.
An apparatus for announcing a call from any place to another, as from a
living-room to an office in a hotel, or for announcing the entering of
any given room or window in a building protected by a burglar alarm.
A usual system comprises for each annunciator an electro-magnet. Its
armature is normally held away from its poles by a spring, and when in
that position a latch connected to the armature holds a little shutter.
When by a push-button or other device a current is sent through a
circuit which includes the electro-magnet the armature is attracted,
this releases the latch and the shutter drops. In dropping it displays a
number, letter or inscription which indicates the locality of the
push-button or other circuit-closing device. Often annunciators are
connected in circuit with a bell.
Fig. 14. ANNUNCIATOR.
35 STANDARD ELECTRICAL DICTIONARY.
Annunciator Clock.
A clock operating an annunciator by making contact at determined times.
Annunciator Drop.
The little shutter which is dropped by some forms of annunciators, and
whose fall discloses a number, character or inscription, indicating
whence the call was sent.
Fig. 15. DROP ANNUNCIATOR.
Fig. 16. ANNUNCIATOR DETACHING MECHANISM.
Annunciator, Gravity Drop.
An annunciator whose operations release shutters which fall by gravity.
Annunciator, Needle.
A needle annunciator is one whose indications are given by the movements
of needles, of which there is usually a separate one for each place of
calling.
Annunciator, Swinging or Pendulum.
An annunciator which gives its indications by displacing from its
vertical position a pendulum or vertically suspended arm.
36 STANDARD ELECTRICAL DICTIONARY.
Anodal Diffusion.
A term in electro-therapeutics; the introduction of a medicine into the
animal system by using a sponge-anode saturated with the solution of the
drug in question. On passing a current the desired result is secured by
cataphoresis, q. v.
Anode.
The positive terminal in a broken metallic or true conducting circuit;
the terminal connected to the carbon plate of a galvanic battery or to
its equivalent in case of any other generator. In general practice it is
restricted to the positive terminal in a decomposition or electrolytic
cell, such as the nickel anode in a nickel-plating bath or the anode of
platinum in a gas voltameter. It is the terminal out of or from which
the current is supposed to flow through the decomposition cell. In
electro-therapeutics the term is used simply to indicate the positive
terminal. In an electrolytic cell the electro-negative substance or
anion goes to the anode. Hence, it is the one dissolved, if either are
attacked. The nickel, copper or silver anodes of the electroplater
dissolve in use and keep up the strength of the bath. The platinum anode
in a gas voltameter is unattacked because the anion cannot act upon it
chemically.
Anodic Closure Contraction.
A physiological change in a living subject produced by the closing of
the electric current; the muscular contraction which takes place beneath
the anode applied to the surface of the body when the circuit is closed,
the kathode being applied elsewhere; it is due, presumably, to direct
action on the motor nerve. It is a term in electro-therapeutics. It is
the converse of anodic opening contraction, q. v. An abbreviation A. C.
C. is often used to designate it.
Anodic Duration Contraction.
A term in electro-therapeutics. On the opening or closing of an electric
circuit, the anode of which is placed over a muscle, a contraction is
observed (see Anodic Closure Contraction--Anodic Opening Contraction).
The above term is used to designate the duration of such contraction. An
abbreviation A. D. C. is often used to designate it.
Anodic Opening Contraction.
The converse of Anodic Closure Contraction, q. v.; it is the contraction
of living muscle beneath or near the anode where the circuit, including
such anode and the body in its course, is closed; a physiological
phenomenon observed in electro-therapeutics to which branch of science
the term belongs. An abbreviation A. O. C. is often used to designate
it.
Anodic Reactions.
A term in electro-therapeutics; the diagnosis of disease by the actions
of the tissue near the anode of a circuit.
Anti-Induction Conductor.
A conductor constructed to avoid induction effects in the conducting
element. Many kinds have been made. A tubular metal shield or envelope
which may be grounded will protect an enclosed conductor to some extent.
Or the conductor may be a double wire twisted around itself, one branch
being used for the regular and the other for the return circuit, thus
constituting a closed metallic circuit. The inductive effects are due to
interrupted or varying currents in neighboring wires and circuits. Many
anti-induction conductors have been invented and patented.
37 STANDARD ELECTRICAL DICTIONARY.
Anti-magnetic Shield.
In general terms a hollow screen of soft iron designed to protect any
mass of steel behind or enclosed by it from magnetization by any magnet
near it, such as a dynamo field magnet. This it does by concentrating
the lines of force within its own mass, so that the space within it or
enclosed by it is comparatively free from lines of force. It is often
applied to watches, and is virtually an iron case in which they are
enclosed.
Antimony.
A metal, one of the elements, atomic weight, 122:
equivalent, 40.6 and 24.4; valency, 3 and 5;
specific gravity, 6.8.
It is a conductor of electricity.
Relative resistance, compressed (silver = 1), 23.60
Specific resistance, 35.50 microhms.
Resistance of a wire,
(a) 1 foot long, weighing 1 grain, 3.418 ohms.
(b) 1 foot long, 1/1000 inch thick, 213.6 "
(c) 1 meter long, weighing 1 gram, 2.384 "
(d) 1 meter long. 1 millimeter thick, 0.4521 "
Resistance of a 1-inch cube, 13.98 microhms.
Approximate percentage resistance per degree C.
(1.8º F. at 20º C. 88º F.) 0.389 per cent.
Elcctro-chemical equivalent (hydrogen = .0105) .2560
(See Thermo-Electric Series.)
Anvil.
An intermittent contact, or "make and break" of the current is sometimes
produced by directly pressing a key down upon a metallic surface, the
two being terminals of the circuit. The surface or stud on which such
pressure is produced is called the anvil. The ordinary telegraph key,
which makes a contact by the pressure of the operator's fingers does it
by making a contact between a contact piece upon the front end of the
key and the anvil. In the induction coil the anvil is also found. Thus
in the cut representing the end of an induction coil and its circuit
breaker in which O and O' and P and P' represent the secondary circuit
terminal connections A is the core of soft iron wires, h is the anvil;
the hammer when resting upon it so as to be in contact closes the
circuit. When the current coming from the primary to the post i, passes
through the hammer and anvil h, and emerges by m, it magnetizes the
core; this attracts the hammer, which is made of or is armed with a mass
of iron. This breaks the circuit. The hammer falls at once on the anvil,
again making the circuit, and the action is repeated with great
rapidity. Hammer and anvil or key and anvil connections should be made
of platinum.
Fig. 17. INDUCTION COIL CIRCUIT BREAKER.
38 STANDARD ELECTRICAL DICTIONARY.
A. O. C.
Abbreviation for Anodic Opening Contraction, q. v.
Aperiodic. adj.
In an oscillating apparatus, or in the oscillating member of apparatus,
the fact of having no reference to time of vibration; dead-beat.
Synonym. Dead-beat.
39 STANDARD ELECTRICAL DICTIONARY.
Fig. 18. ARAGO'S DISC.
Arago's Disc.
An apparatus consisting of a disc of copper mounted horizontally, or on
a vertical spindle, and so arranged as to be susceptible of rapid
rotation. Immediately over it, and best with a pane of glass
intervening, a magnetic needle is mounted on a pivot directly over the
axis of the disc. If the disc is rotated the lines of force of the
magnet are cut by it, and consequently currents are produced in the
copper. These currents act upon the needle and cause it to rotate,
although quite disconnected. It is advisable for the needle to be strong
and close to the disc, which should rotate rapidly.
Arc v.
To form a voltaic arc.
Arc, Compound.
A voltaic arc springing across between more than two electrodes.
Arc, Metallic.
The voltaic arc produced between terminals or electrodes of metal. The
characteristics of such arc as contrasted with the more usual arc
between carbon electrodes are its greater length for the same
expenditure of energy, its flaming character and characteristic colors
due to the metals employed. It is sometimes, for the latter reason, used
in spectroscopic investigations.
Arc Micrometer.
A micrometer for measuring the distance between the electrodes of a
voltaic arc.
Arc, Simple.
A voltaic arc produced, as usual, between only two electrodes.
40 STANDARD ELECTRICAL DICTIONARY.
Arc, Voltaic.
The voltaic arc is the arc between two carbon electrodes slightly
separated, which is produced by a current of sufficient strength and
involving sufficient potential difference. The pencils of carbon are
made terminals in a circuit. They are first placed in contact and after
the current is established they are separated a little. The current now
seems to jump across the interval in what sometimes appears an arch of
light. At the same time the carbon ends become incandescent. As regards
the distance of separation with a strong current and high electro-motive
force, the arc may be several inches long.
The voltaic arc is the source of the most intense heat and brightest
light producible by man. The light is due principally to the
incandescence of the ends of the carbon pencils. These are differently
affected. The positive carbon wears away and becomes roughly cupped or
hollowed; the negative also wears away, but in some cases seems to have
additions made to it by carbon from the positive pole. All this is best
seen when the rods are slender compared to the length of the arc.
It is undoubtedly the transferred carbon dust which has much to do with
its formation. The conductivity of the intervening air is due partly,
perhaps, to this, but undoubtedly in great measure to the intense
heating to which it is subject. But the coefficient of resistance of the
intervening air is so much higher than that of any other part of the
circuit that an intense localization of resistance occurs with
corresponding localization of heating effect. This is the cause of the
intense light. Thus if the carbons are but 1/32 of an inch apart as in a
commercial lamp the resistance may be 1.5 ohms. The poor thermal
conductivity of the carbon favors the concentration of heat also. The
apparent resistance is too great to be accounted for by the ohmic
resistance of the interposed air. A kind of thermoelectric effect is
produced. The positive carbon has a temperature of about 4,000° C.
(7,232° F.), the negative from 3,000° C. (5,432° F.) to 3,500° C.
(6,322° F.). This difference of temperature produces a
counter-electro-motive force which acts to virtually increase the
resistance of the arc. The carbon ends of an arc can be projected with
the lantern. Globules are seen upon them due to melted silica from the
arc of the carbon.
Fig. 19. EXPERIMENTAL APPARATUS FOR PRODUCING THE VOLTAIC ARC.
41 STANDARD ELECTRICAL DICTIONARY.
Areometer.
An instrument for determining the specific gravity of a fluid. It
consists of an elongated body ballasted so as to float vertically and
provided with a mark or a scale. It floats deeper in a light than in a
heavy liquid. If it carries but one mark weights are added until that
mark is reached, when the weights required give the specific gravity. Or
the scale may give the reading directly based upon the depth to which it
sinks. Areometers are often made of glass, ballasted with shot or
mercury enclosed in their bottom bulb as shown. They are used in
regulating battery solutions, and in watching the charging and
discharging of storage batteries.
Fig. 20. AREOMETER
Fig. 21. BEAD AREOMETER
Areometer, Bead.
A tube of glass containing beads of different specific gravities. It has
apertures at top and bottom. When immersed in a liquid, the same fills
it, and the specific gravity within certain limits, depending on the
factors of the beads, is shown by the beads which float and those which
sink. It is used for storage batteries and other purposes where acids
and solutions have to be tested.
Argyrometry.
The method of ascertaining the weight and inferentially the thickness of
an electroplater's deposit of silver. It is done by weighing the article
before and after plating.
Arm.
The four members of a Wheatstone bridge, q. v., are termed its arms.
Referring to the diagram of a bridge, P, Q, R, S, are the arms.
Fig. 22. DIAGRAM OF WHEATSTONE'S BRIDGE.
Armature.
(a.) A mass or piece of iron or steel, or a collection of pieces of iron
designed to be acted on by a magnet. While nickel or cobalt might be
used, they rarely or never are except in experimental apparatus. The
armature of a permanent horse shoe magnet is simply a little bar of soft
iron. When the magnet is not in use it is kept in contact with the poles
with the idea of retaining its magnetism. It is then said to be used as
a keeper. A bar magnet does not generally have an armature. The armature
is also used to exhibit the attraction of the magnet.
Sometimes an armature is made of steel and is permanently magnetized.
Such an armature, termed a polarized armature, is repelled when its like
poles are opposed to like poles of the magnet and otherwise is attracted
with force due to the sums of the magnetism. If the magnet is
sufficiently powerful depolarization of the armature may ensue when like
poles are opposed to like poles. Polarized armatures are used in various
appliances, magneto generators, telegraphic instruments and others.
(b) In a dynamo or Motor the mass of laminated iron or of wire which
carries the coils of insulated wires which are caused to rotate in the
field of force of the field magnets in order to establish and maintain
potential difference with its accompanying current, or which rotates
under the effects of a current in a motor. (See Dynamo Electric
Generator.)
The work of the armature core is twofold. It acts as a portion of the
magnetic circuit, conducting the lines of force, and by virtue of its
high permeability or multiplying power concentrating a number of the
lines of force through its own substance. To enable it to act with
efficiency in this direction it should be made of iron of the highest
permeability, and should approach as closely as possible to the armature
cores consistent with leaving space for the wire winding. It next acts
as a support for the wires which are to be swept through the field of
force. Thus it acts both to establish a strong field and then acts as a
carrier for the wires which are to be cut by the wires in question. In
connection with this subject the different definitions under Armature,
Dynamo, Commutator, Induction and similar topics may be consulted.
(c) See Armature of Influence Machine.
(d) See Armature of Leyden Jar or Static Condenser.
42 STANDARD ELECTRICAL DICTIONARY.
Armature, Bar.
An armature in a dynamo or motor whose winding is made up of conductors
in the form of bars, round, rectangular and of other sections. This type
of armature conductor is objectionable as Foucault currents are produced
in it. It is found best to laminate or subdivide low resistance armature
windings.
[Transcriber's Note: Foucault currents are also called eddy currents.]
Armature, Bipolar.
An armature in which two poles are induced by the field. A bipolar field
magnet produces a bipolar armature.
Armature Bore.
The cylindrical space defined by the pole pieces of a dynamo or motor
within which the armature rotates.
Synonym--Armature Chamber.
43 STANDARD ELECTRICAL DICTIONARY.
Armature, Closed Coil.
An armature for a motor or dynamo, the ends of all of whose coils are
united, so as to be in one closed circuit all the way around.
Fig. 23. CLOSED COIL GRAMME RING ARMATURE.
Armature Coil, or Coils.
The insulated wire wound around the core of the armature of an electric
current generator or motor.
Armature Core.
The central mass of iron on which the insulated wire, to be rotated in
the field of an electric current generator or motor, is wound. (See
Dynamo-electric Machine and Motor, Electric.)
Armature, Cylinder.
An armature of the Gramme ring type, but longer in the axial direction,
so that its core resembles a long hollow cylinder, the wire being wound
inside and outside as in the Gramme ring. (See Gramme Ring.)
Armature, Disc.
(a) An armature of a dynamo electric machine or motor in which the coils
are wound so as to be flat and are carried on the face of a disc forming
the core or part of the core of the armature. S. P. Thompson treats it
as a modified drum armature extended radially, the outer periphery
corresponding to the back end of the drum. The poles of the field are
generally placed to face the side or sides of the disc.
(b) Another type of disc armature has its wire wound on bobbins arranged
around the periphery of a disc.
In disc armatures there is often no iron core, their thinness enabling
this to be dispensed with.
44 STANDARD ELECTRICAL DICTIONARY.
Fig. 24. DISC ARMATURE OF FRITSCHE MACHINE.
Fig. 25. PLAN OF WINDING PACINOTTI'S DISC ARMATURE.
Armature, Discoidal Ring.
In a dynamo an armature of the shape of a ring of considerable radial
depth of section as compared to its axial depth. It is generally made of
iron ribbon or thin band wound to the proper size.
Synonym--Flat Ring Armature.
45 STANDARD ELECTRICAL DICTIONARY.
Armature, Drum.
An armature for a dynamo or motor, consisting of a cylinder of iron
preferably made up of discs insulated from each other by thin shellacked
paper, or simply by their oxidized surfaces, and wound with wire
parallel to the axis where it lies on the cylindrical periphery and
crossing the heads approximately parallel to the diameter. It operates
practically on the same principle as a Gramme Ring Armature. (See Gramme
Ring.)
Synonym--Cylindrical Armature.
Armature Factor.
The number of conductors on an armature, counted or enumerated all
around its external periphery.
Armature, Hinged.
An armature pivoted to the end of one of the legs of an electro-magnet
so as to be free to swing and bring its other end down upon the other
pole.
Fig. 26. HINGED ARMATURES OF CLUB-FOOT ELECTRO MAGNETS.
Armature, Hole.
An armature whose core is perforated to secure cooling.
Synonym--perforated Armature.
Armature, Intensity.
An armature wound for high electro-motive force. A term little used at
the present time.
Armature Interference.
A limit to the ampere turns permissible on a given armature is found in
the increase of cross magnetizing effect, q. v., the increased lead
necessitated, and the growth of the demagnetizing power. All such
perturbing effects are sometimes expressed as armature interference.
46 STANDARD ELECTRICAL DICTIONARY.
Armature, Load of.
The circumflux, q. v., of the armature, or the ampere turns of the same.
The maximum load which can be carried by an armature without sparking is
directly proportional to the radial depth of core and to the length of
the gap, and inversely proportional to the breadth of the polar span.
Armature, Multipolar.
An armature in which a number of poles greater than two is determined by
the field. A multipolar field is employed for its production.
Armature, Neutral.
An armature of a magnet or telegraph relay which is not polarized or
magnetized.
Synonym--Non-polarized Armature--Neutral Relay Armature.
Armature of Influence Machine.
Pieces of paper pasted on the stationary plate of an electric machine of
the Holtz type.
Armature of Leyden Jar or Static Condenser.
The inner and outer tin-foil coatings of a Leyden jar or other
condenser.
Armature, Open Coil.
An armature of a dynamo or motor on which the coils are not joined in
one closed circuit, but have their ends or some of them separated, and
connected each to its own commutator bar or each set to their own bar.
Fig. 27. OPEN COIL RING ARMATURE.
47 STANDARD ELECTRICAL DICTIONARY.
Armature, Pivoted.
An armature for an electro-magnet mounted on a pivot, which is at right
angles to the yoke or parallel with the legs of the magnet, so as to be
free to rotate. When the magnet is excited the armature is drawn into
line or approximately so with its base or yoke. The system is used in
some telegraph apparatus.
Armature Pockets.
Spaces or recesses in armatures provided for the reception of the coils.
Armature, Polarized.
An armature made of steel or having a steel core to which permanent
magnetism has been imparted. Such are used in some forms of magneto
current generators, and in telegraphic instruments. (See Relay,
Polarized.)
Armature, Pole.
An armature having coils wound on separate poles projecting radially all
around the periphery of its central hub or disc, or projecting
internally from a ring-like frame, their ends facing the field magnet.
Synonym--Radial Armature.
Armature, Quantity.
An armature of a dynamo or motor wound for current of large quantity.
The term is now but little used.
Armature-Reactions.
When an armature is running in an active dynamo a series of
reactions is established, the more important of which are:
I. A tendency to cross-magnetize the armature.
II. A tendency to spark at the brushes.
III. A tendency for the armature current to demagnetize on account of
the lead which has to be given to the brushes.
IV. Variations in the neutral points as more or less current is taken
from the machine.
V. Heating of armature, both core and conductors, and of pole pieces,
which heating is due to Foucault currents.
Armature, Revolving, Page's.
An early form of motor. The field is produced by a permanent magnet.
Above its poles is a soft iron armature wound with a coil of insulated
wire. A two-part commutator with contact springs conveys the current to
the coil. The whole is so arranged that the polarity of the armature, as
induced by the coil, through which a current is passed, is reversed as
its ends sweep by the poles of the magnet. Then it is repelled from the
poles and swings through 180° to have its polarity reversed and to go
through the next 180°, and so on. Thus it rotates at a very high rate of
speed.
In the cut showing the elevation A, B, is the armature; f, g, the
springs or brushes; h, the commutator with its sections o, i. In the
section of the commutator W, W, designate the springs or brushes, A, the
vertical spindle carrying the armature and commutator, and S, S, the
commutator sections.
48 STANDARD ELECTRICAL DICTIONARY.
Fig. 28. PAGE'S REVOLVING ARMATURE.
Fig. 29. SECTION OF COMMUTATOR OF PAGE'S REVOLVING ARMATURE.
W, W, Brushes; A, Spindle; S, S, Armature Segments.
Armature, Ring.
An armature whose core is in the shape of a ring, as the Gramme Ring
Armature. (See Figs. 23 & 27.)
49 STANDARD ELECTRICAL DICTIONARY.
Armature, Rolling.
(a) An armature for a permanent horseshoe magnet consisting of a
straight cylinder of soft iron on which a heavy wheel is mounted. When
the legs of the magnet are inclined downward and the bar is laid across
them it rolls down to the poles, across their ends, and back up the
under side. It is merely a magnetic toy or illustrative experiment.
Synonym--Wheel Armature.
(b) Another form consists of little bars of iron with brass discs
attached to the ends. On placing two of these together and bringing the
poles of a magnet near them, as shown, they become magnetized with like
polarity by induction and repel each other, rolling away in opposite
directions.
Fig. 30. ROLLING OR WHEEL ARMATURE.
Fig. 31. ROLLING ARMATURES.
Armature, Shuttle.
The original Siemens' armature, now discarded. The core was long and
narrow, and its cross section was nearly of the section of an H. The
grooves were wound full of wire, so that the whole formed almost a
perfect cylinder, long and narrow comparatively. (See Winding Shuttle.)
Synonym--Siemens' Old Armature--Girder Armature--H Armature.
Fig. 32. SHUTTLE OR H ARMATURE.
Armature, Spherical.
An armature of a dynamo which is wound on a spherical core, so as to be
almost a sphere. It is employed in the Thomson-Houston dynamo, being
enclosed in a cavity nearly fitting it, formed by the pole pieces.
Armature, Stranded Conductor.
A substitute for bar-armatures in which stranded copper wire conductors
are substituted for the solid bar conductors, to avoid Foucault
currents. (See Armature, Bar.)
50 STANDARD ELECTRICAL DICTIONARY.
Armature, Unipolar.
An armature of a unipolar dynamo. (See Dynamo Unipolar.)
Armor of Cable.
The metal covering, often of heavy wire, surrounding a telegraph or
electric cable subjected to severe usage, as in submarine cables.
Synonym--Armature of Cable.
Arm, Rocker.
An arm extending from a rocker of a dynamo or motor, to which arm one of
the brushes is attached. (See Rocker.) Ordinarily there are two arms,
one for each brush.
Articulate Speech.
Speech involving the sounds of words. It is a definition which has
acquired importance in the Bell telephone litigations, one contention,
concerning the Bell telephone patent, holding that the patentee did not
intend his telephone to transmit articulations, but only sound and
music.
Astatic. adj.
Having no magnetic directive tendency due to the earth's magnetism.
Examples are given under Astatic Needle; Circuit, Astatic; and
Galvanometer Astatic.
Fig. 33. NOBILI'S PAIR.
FIG. 34. VERTICAL PAIR ASTATIC COMBINATION.
Astatic Needle.
A combination of two magnetic needles so adjusted as to
have as slight directive tendency as possible. Such a pair of needles
when poised or suspended will hardly tend to turn more to one point of
the compass than another. The combination is generally made up of two
needles arranged one above the other, with their poles in opposite
directions. This combination is usually called Nobili's pair. If of
equal strength and with parallel magnetic axes of equal length they
would be astatic. In practice this is very rarely the case. A resultant
axis is generally to be found which may even be at right angles to the
long axis of the magnets, causing them to point east and west. Such a
compound needle requires very little force to turn it one way or the
other. If one of the needles is placed within a coil of insulated wire a
feeble current will act almost as strongly to deflect the system as if
the other was absent, and the deflection will only be resisted by the
slight directive tendency of the pair of needles. This is the basis of
construction of the astatic galvanometer. Sometimes coils wound in
opposite directions and connected in series, or one following the other,
surround both needles, thus producing a still greater effect of
deflection.
Other astatic needles are shown in the cuts below. [Figures 33 to 35.]
51 STANDARD ELECTRICAL DICTIONARY.
FIG. 35. SIMPLE ASTATIC NEEDLE.
Asymptote.
A line continuously approached by a curve, but which the curve, owing to
its construction or nature of curvature, can never touch, be tangent to,
or intersect.
Atmosphere.
(a) A term applied to the atmospheric pressure as a practical unit of
pressure equal to 15 lbs. to the square inch as generally taken. It is
really about 14.7 lbs. per square inch, or 1,033 grams per square
centimeter.
(b) Air, q. v.
Atmosphere Residual.
The atmosphere left in a vessel after exhaustion. The term may be
applied to any gas. In an incandescent lamp after flashing the residual
atmosphere consists of hydro-carbons.
Atmospheric Electricity.
The electricity of the atmosphere, rarely absent, but often changing in
amount and sign. Benjamin Franklin, in a memoir published in 1749,
indicated the method of drawing electricity from the clouds by pointed
conductors. In June, 1752, he flew a kite and by its moistened cord drew
an electric spark from the clouds, confirming his hypothesis that
lightning was identical with the disruptive discharge of electricity. To
observe electricity in fine weather a gold-leaf or other electroscope
may be connected to the end of a long pointed insulated conductor. The
electricity during thunderstorms can be shown by a similar arrangement,
or burning alcohol or tinder gives an ascending current of warm air that
acts as a conductor. Quite elaborate apparatus for observing and
recording it have been devised. Atmospheric electricity is usually
positive, but occasionally negative. When the sky is cloudless it is
always positive, increasing with the elevation and isolation of the
place. In houses, streets, and under trees no positive electricity can
be found. In the Isle of Arran, Scotland, a rise of 24 to 48 volts per
foot of increase in elevation was found by Sir William Thomson. At
sunrise the electrification of the air is feeble, it increases towards
noon and decreases again to reach a second maximum a few hours after
sunset. It increases with the barometric pressure generally. In cloudy
weather it is sometimes negative and the sign often changes several
times in the same day. In a thunderstorm the changes in sign and
potential are very rapid. The cause of atmospheric electricity is far
from clear. Tait attributes it to a contact effect between air and water
vapor, Solmeke to friction of water vesicles against ice particles in
the upper atmosphere, he first showing that the two may coexist. The
cause of the enormous increase of potential producing lightning is
attributed to the decreased capacity due to the change of water from
cloud vesicles to drops, thus diminishing the electrostatic capacity of
the water in question. (See Lightning.)
52 STANDARD ELECTRICAL DICTIONARY.
Atom.
The ultimate particle or division of an elementary substance; the
smallest part that can exist in combination, and one which cannot exist
alone. An elementary substance is composed of molecules just as truly as
a compound one, but the atoms in the molecule of an elementary substance
are all precisely alike. Hence atoms are the units of chemistry, they
have to do with combinations, but the physical unit, the smallest
particle of matter that can have an independent existence, is the
molecule. The two are often confounded, especially by writers of a few
years ago, so that by "atom" the molecule is often meant. There is
nothing to be said of their size or mass. All such calculations refer to
the molecule, q. v., often spoken of and called the atom.
[Transcriber's note: Yet to be discovered: electron--1897 (5 years),
proton--1920 (28 years), neutron--1932 (30 years), quark--1961 (69 years).]
Atomic Attraction.
The attraction of atoms for each other, in virtue of which they combine
into molecules; chemical affinity, q. v., treats principally of this,
although molecular attraction also plays a part in it.
Atomic Heat.
The product of the atomic weight of a substance by its specific heat.
This product is approximately the same, 6.4; this approximation is so
close that it is of use in determining the valency and atomic weights of
substances. The atomic weight of a substance therefore represents the
approximate number of gram-calories required to raise one gram-atom, q.
v., of such substance through 1° C. (1.8° F.)
Atomicity.
The quantivalence or valency of the atoms; the number of combination
bonds, or bonds of affinity, possessed by the atoms of any substance.
Thus two atoms of hydrogen combine with one atom of oxygen, and three of
oxygen with one of sulphur, forming saturated compounds. Therefore,
taking hydrogen as of single atomicity or a monad, oxygen is of double
atomicity or a dyad, and sulphur is of six-fold atomicity, or a hexad.
The elements are thus classified into seven orders of atomicities, thus:
1, Monads or Univalent elements, Hydrogen, etc.
2, Dyads or Bivalent " Oxygen, etc.
3, Triads or Trivalent " Nitrogen, etc.
4, Tetrads or Quadrivalent " Lead, etc.
5, Pentads or Quinquivalent " Phosphorous, etc.
6, Hexads or Sexivalent " Chromium, etc.
7, Heptads or Septivalent " Chromium, etc.
The same element often possesses several atomicities. Barium is
generally a dyad, sometimes a tetrad; nitrogen acts as a monad, dyad,
triad, tetrad and pentad. The familiar electrolysis of water, giving two
volumes of hydrogen to one of oxygen, is one of the illustrations of the
theory indicating that two atoms of hydrogen are combined with one of
oxygen.
53 STANDARD ELECTRICAL DICTIONARY.
Atomic Weight.
The number expressing the relative weight of the atom of any substance,
that of hydrogen being generally taken as unity. This is the universal
system, although any other element might be taken as the basis of the
system. The whole theory of atomic weights is based on the
indivisibility of the atom and on the theory of atomicity, q. v. (See
Equivalents.)
[Transcriber's note: The standard is now the isotope carbon-12 as
exactly 12.]
Attraction.
The tendency to approach and adhere or cohere, shown by all forms of
matter. It includes gravitation, cohesion, adhesion, chemical affinity
and other forms, and is opposed by repulsion, and is sometimes overcome
by it, although it may be assumed to be always present. See the
different kinds of attractions under their titles: Atomic Attraction,
Electro-magnetic Attraction and Repulsion, Electro Static Attraction and
Repulsion, Electro-dynamic Attraction and Repulsion; Magnetic Attraction
and Repulsion; Molar Attraction.
Audiometer.
An apparatus for obtaining a balance of induction from two coils acting
upon a third. The third is placed between the other two and is free to
move towards either. A scale is provided to show the extent of its
movement. A varying or interrupted current being passed through the two
outer coils, the preponderating current will produce the most induction
if the central coil is equidistant. It can always be moved to such a
point that there will be no inductive effect, one counteracting the
other. Thus its position measures the relative induction. A telephone is
in circuit with the intermediate coil and is used to determine when its
position is such that no current is induced in it. It is sometimes used
as a direct test of hearing. (See Hughes' Induction Balance.)
Synonym--Acoutemeter.
Aura, Electrical.
The blast of air produced at highly electrified points.
Aurora.
A luminous display seen in the northern heavens in the northern
hemisphere, where it is the Aurora Borealis, and seen in the southern
heavens in the southern hemisphere, where it is called Aurora Australis,
or indifferently for either, the Aurora Polaris. It takes the form of
pale luminous bands, rays and curtains varying in color. Near the poles
they are very numerous. A French commission observed 150 auroras in 200
days. Their height is variously estimated at from 90 to 460 miles; they
are most frequent at the equinoxes and least so at the solstices. There
is a secular variation also, they attain a maximum of occurrence every
11 years together with sun spots, with a minimum 5 or 6 years after the
maximum. There is also a period of 60 years, coincident with
disturbances in the earth's magnetism. Various attempts have been made
to account for them. They have a constant direction of arc with
reference to the magnetic meridian (q. v.) and act upon the magnetic
needle; in high latitudes they affect telegraph circuits violently.
There is a strong probability that they represent electric currents or
discharges. De la Rive considers them due to electric discharges between
the earth and atmosphere, which electricities are separated by the
action of the sun in equatorial regions. According to Balfour Stewart,
auroras and earth currents.(q. v.) may be regarded as secondary currents
due to small but rapid changes in the earth's magnetism. The subject is
very obscure. Stewart treats the earth as representing the magnetic core
of an induction coil, the lower air is the dielectric, and the upper
rarefied and therefore conducting atmosphere is the secondary coil. This
makes the aurora a phenomenon of induced currents. Then the sun may be
regarded as the instigator of the primary changes in the earth's lines
of force representing the primary of an induction coil.
[Transcriber's note: Solar wind, streams of electrons and protons,
interacting with the earth's magnetic field causes aurora. Neither
electrons (1897) nor protons (1920) were known in 1892. The Soviet
satellite Luna first measured the solar wind in 1959. Even today
increased understanding of solar and auroral phenomenon continues.]
54 STANDARD ELECTRICAL DICTIONARY.
Austral Pole.
The north pole of the magnet is thus called sometimes in France; the
austral pole of a magnet is the one which points towards the north polar
regions As unlike magnetic poles attract each other, it is but rational
to call the north-seeking pole of the magnet the south or Austral Pole.
In the same nomenclature the south pole of a magnet, or the
south-seeking pole, is called the Boreal Pole.
A. W. G.
Abbreviation for American Wire Gauge, q. v.
Axis, Electric.
The electric axis of a pyroelectric crystal, such as a tourmaline
crystal; the line connecting the points of greatest pyroelectric
excitability.
Axis of Abscissa.
In a system of rectilinear, or right angle co-ordinates, the horizontal
axis. (See Co-ordinates.)
Synonym--Axis of X.
Axis of Ordinates.
In a system of rectilinear right angle co-ordinates, the vertical axis.
(See Co-ordinates.)
Synonym--Axis of Y.
Azimuth.
The angle between the plane of the meridian and the plane of an azimuth
circle, q. v.
Azimuth Circle.
A great circle, whose plane passes through the zenith or point of the
heavens directly overhead; any great circle in whose plane the vertical
at the point of observation is included.
Each celestial body has or determines an azimuth circle.
55 STANDARD ELECTRICAL DICTIONARY.
B.
(a) Abbreviation for Baumé, a hydrometer scale. (See Baumé.) Thus 10º B.
means "ten degrees Baumé."
(b) Symbol for the coefficient of induced magnetization, or the number
of lines per square centimeter induced in a magnetic circuit or in any
specified part of it.
B. A.
Abbreviation for British Association. It is prefixed to standards fixed
by the committee of the British Association for the Advancement of
Science. Thus the B. A. ohm means the British Association ohm, a measure
of resistance which is equal to the resistance of a column of mercury
104.9 centimeters long and one square millimeter area of cross-section.
(See Ohm.)
Back Induction.
A demagnetizing force produced in a dynamo armature when a lead is given
the brushes. The windings by such setting of the brushes are virtually
divided into two sets, one a direct magnetizing set, the other a cross
magnetizing set. The latter have a component due to the obliqueness of
the neutral line, which component is demagnetizing in its action.
Back Shock or Stroke of Lightning.
A lightning stroke received after the main discharge of the lightning,
and caused by a charge induced in neighboring surfaces by the main
discharge. The discharge affects the evenness of distribution of
surrounding surfaces so that a species of secondary discharge is
required to make even the distribution, or to supply charge where needed
to bind an opposite one. The effects are much lese severe as a rule than
those of the main charge, although the back stroke has caused death. The
back stroke is sometimes felt a considerable distance from the place of
the original lightning stroke.
Synonym--Return Stroke.
Back Stroke.
(a) In telegraphy the return stroke of the lever in a telegraph sounder,
striking the end of the regulating screw with a sound distinct from that
which it produces on the forward stroke as it approaches the magnet
poles. It is an important factor in receiving by ear or sound reading.
(b) See Back Shock or Stroke of Lightning.
Balance.
(a) Wheatstone's Bridge, q. v., is sometimes termed the Electric
Balance.
(b) A suspension or torsion balance is one which includes a filament or
pair of filaments to whose lower end or ends are attached a horizontal
indicator often called a needle, or a magnetic needle. (See Torsion
Balance.)
(c) See Induction Balance, Hughes'.
(d) For Thermic Balance, see Bolometer.
(e) See Balance, Ampere.
56 STANDARD ELECTRICAL DICTIONARY.
Balance, Ampere.
A class of electrical measuring instruments due to Sir William Thomson
may be grouped under this head.
The instrument is a true balance or scales such as used for weighing. It
is supported by a torsional wire support in place of knife edges. At
each end it carries a circle of wire through which the current to be
tested is passed. The torsional wire support enables the current to be
carried to these wire rings. Above and below each of these rings are two
similar rings, also connected so as to receive the current. They are so
connected that the current shall go through them in opposite senses.
When a current passes, therefore, one of these rings repels and one
attracts the balanced ring.
The extent of this action measures the intensity of the current. A
sliding weight moving along a graduated scale on the balance is used to
bring the balance beam into equilibrium when the current is passing. The
degree of displacement of this weight gives the strength of the current
in amperes.
These balances are made for different currents. Thus there is a
centi-ampere balance, deka-ampere balance and others, as well as an
ampere balance.
Balata.
A gum used as an insulating material. It is the inspissated juice of a
sapotaceous tree, the bullet tree, Mimusops globosa, of tropical
America, from the Antilles to Guiana. It is intermediate in character
between caoutchouc and gutta percha. It is superior to gutta percha in
some respects, being very slightly acted on by light.
Synonym--Chicle.
B. & S.. W. G.
Abbreviation for Brown & Sharpe Wire Gauge; the regular American Wire
Gauge. (See Wire Gauge, American.)
Barad.
An absolute or fundamental unit of pressure, equal to one dyne per
square centimeter.
Barometer.
An apparatus for measuring the pressure exerted by the atmosphere. It
consists, in the mercurial form, of a glass tube, over 31 inches long,
closed at one end, filled with mercury and inverted, with its open end
immersed in a cistern of mercury. The column falls to a height
proportional to the pressure of the atmosphere from 30 to 31 inches at
the sea level. The "standard barometer" is a height of the mercury or of
the "barometric column" of 30 inches or 760 centimeters, measured from
the surface of the mercury in the cistern.
The column of mercury is termed the barometric column. Above it in the
tube is the Torricellian vacuum.
[Transcriber's note: More accurately, 29.92 inches of mercury or 14.696
PSI.]
Bars of Commutators.
The metal segments of a commutator of a dynamo or motor. They are made
of bars of copper, brass or bronze insulated from one another. (See
Commutator.)
Synonyms--Segments, Commutator Segments, Commutator Bars.
57 STANDARD ELECTRICAL DICTIONARY.
Bath.
(a) In electro-plating the solution used for depositing metal as
contained in a vat or tank; as a silver, copper, or nickel bath used for
plating articles with silver, copper, or nickel respectively.
(b) In electro-therapeutics a bath with suitable arrangements,
electrodes and connections for treating patients with electricity. It is
termed an electric bath or electro-therapeutic bath.
Bath, Bipolar Electric.
In electro-therapeutics a bath in which the electrodes are both immersed
in the water. The patient placed between them receives part of the
discharge. The electrodes are large copper plates, termed shovel
electrodes.
Bath, Electric Shower.
An electro-medical shower bath. The patient is placed on a metallic
stove or support connected to one of the electric terminals. Water
slightly alkaline is showered upon him. The other electrode is in
connection with the water. The rain of drops and streamlets is the
conductor of the current or discharge.
Bath, Multipolar Electric.
An electro-medical bath with a number of electrodes instead of two.
Bath, Stripping.
In electro-plating a solution used for dissolving and thus removing the
plating from any object. The stripping bath is of the same general type
as the plating bath for the same metal as the one to be dissolved. The
object to be "stripped" is made the anode of a plating circuit, and as
the current acts the old plating is attacked and dissolves, leaving the
body of the article bare. It is simply the operation of plating
reversed. The same term is applied to baths acting by simple solution.
Stripping baths are described under the different metals as Silver Bath,
Stripping--Gold Bath, Stripping.
Bath, Unipolar Electric.
An electro-medical bath, in which only one electrode connects with the
water of the bath. The second electrode is supported above the bath. The
patient touches this while in the water whenever electric action is
desired.
FIG. 36. THREE WIRE MOULDING OR BATTEN.
FIG. 37. TWO WIRE MOULDING OR BATTEN.
58 STANDARD ELECTRICAL DICTIONARY.
Batten.
A strip of wood grooved longitudinally for holding wires in wiring
apartments for electric light or power. In use they are fastened to the
wall, grooves inward, or else grooves outward, with the wires lying in
the grooves and covered with the covering strip. For two wire work each
batten contains two grooves; for the three wire system it contains three
grooves.
Synonym--Moulding.
Battery.
A combination of parts or elements for the production of electrical
action. The term is principally applied to voltaic batteries, but there
are also magnetic batteries, batteries of Leyden jars, and other
combinations, described in their places, which come under this category.
[Transcriber's note: A group of similar items such as questions,
machines, parts, guns, or electric cells.]
Battery, Acetic Acid.
A battery whose active solution or excitant is acetic acid or vinegar.
This acid has been used by Pulvermacher in his medical battery, as being
a substance found in every household in the form of vinegar. It is now
but little used.
Battery, Alum.
A battery using as excitant a solution of alum. This battery has had
some application for electric clocks, but only to a limited extent.
Fig. 38. BALLOON OR FLASK BATTERY.
Battery, Aluminum.
A battery in which aluminum is the negative plate and aluminum sulphate
the excitant. It is mounted like the gravity battery. Its electro-motive
force is 0.2 volt.
59 STANDARD ELECTRICAL DICTIONARY.
Battery, Bagration.
A battery with zinc and carbon electrodes immersed in earth sprinkled
with sal ammoniac (ammonium chloride). The copper is preferably first
immersed in sal ammoniac solution and dried, until a green layer is
formed on its surface.
The battery is highly praised for its constancy by De la Rive, but may
be regarded as obsolete.
Battery, Balloon.
A form of gravity battery into whose centre a globular flask, B, is
inverted, which is filled before inversion with copper sulphate, of
which 2 lbs. are used, and water, so as to remain full. This acts as a
reservoir of copper sulphate, which it constantly supplies. The glass
jar is closed with a perforated wooden cover.
Battery, Banked.
(a) A battery arranged to feed a number of separate circuits.
(b) A battery connected in parallel or in multiple arc.
Battery, Bichromate.
A battery with amalgamated zinc and carbon plates, with an exciting
fluid composed of sulphuric acid, water, and potassium bichromate. For
formula of such solutions see Electropoion Fluid--Kookogey's
Solution--Poggendorff's Solution--Trouvé's Solution--Delaurier's
Solution, and others. (See Index.)
Battery, Bunsen.
A two fluid porous cell battery. The negative plate is carbon, the
positive plate, amalgamated zinc. The depolarizer is nitric acid or
electropoion fluid, q.v., in which the carbon is immersed. The last
named depolarizer or some equivalent chromic acid depolarizing mixture
is now universally used. The excitant is a dilute solution of sulphuric
acid. Originally the carbon was made cylindrical in shape and surrounded
the porous cups, in which the zinc was placed. This disposition is now
generally reversed. The electro-motive force is 1.9 volts. The
depolarizing solution is placed in the compartment with the carbon. The
excitant surrounds the zinc.
Fig. 39. BUNSEN'S BATTERY.
60 STANDARD ELECTRICAL DICTIONARY.
Battery, Cadmium.
A battery in which cadmium is the negative plate, sulphate of cadmium
solution the excitant and depolarizer, and zinc the positive plate.
Electro-motive force, .31 volt or about one third of a Daniell cell. It
is mounted like a gravity battery.
Battery, Callan.
A modification of Grove's battery. Platinized lead is used for the
negative plate, and as a depolarizer a mixture of 4 parts concentrated
sulphuric acid, 2 parts of nitric acid, and 2 parts of a saturated
solution of potassium nitrate. (See Battery, Grove's.)
Battery, Camacho's.
A battery with carbon negative and amalgamated zinc positive electrodes.
The carbon is contained in a porous cup, packed with loose carbon.
Electropoion or other fluid of that type serves as excitant and
depolarizer, and is delivered as shown from cell to cell by syphons.
Fig. 40. CAMACHO'S BATTERY.
Battery, Carré's.
A Daniell battery for whose porous cup a vessel or species of sack made
of parchment paper is substituted. The battery has been used for
electric light, and has been run for 200 successive hours, by replacing
every 24 hours part of the zinc sulphate solution by water.
61 STANDARD ELECTRICAL DICTIONARY.
Battery, Cautery.
A battery used for heating a platinum wire or other conductor used for
cauterization in electro-therapeutics. The term is descriptive, not
generic.
Battery, Chloric Acid.
A battery of the Bunsen type in which an acidulated solution of
potassium chlorate is used as depolarizer.
Battery, Chloride of Lime.
A battery in which bleaching powder is the excitant. The zinc electrode
is immersed in a strong solution of salt, the carbon in a porous vessel
is surrounded with fragments of carbon and is packed with chloride of
lime (bleaching powder). There is no action on open circuit. It has to
be hermetically sealed on account of the odor. Its electro-motive force
is--initial, 1.65 volts; regular, 1.5 volts.
Synonym--Niaudet's Battery.
Battery, Chromic Acid.
Properly a battery in which chromic acid is used as a depolarizer. It
includes the bichromate battery. (See Battery, Bichromate.)
Battery, Closed Circuit.
A battery adapted by its construction to maintain a current on a closed
circuit for a long time without sensible polarization. The term is
merely one of degree, for any battery becomes exhausted sooner or later.
As examples the Grove, Bunsen or Daniell batteries may be cited.
62 STANDARD ELECTRICAL DICTIONARY.
Fig. 41. COLUMN BATTERY.
Battery, Column.
The original Volta's pile. It consists of a series of compound circular
plates, the upper or lower half, A, copper; the other, Z, of zinc.
Between each pair of plates some flannel or cloth, u, u, is laid, which
is saturated with dilute acid. As shown in the cut, the parts are laid
up in two piles, connected at the top with a bar, c, c, and with vessels
of acidulated water, b, b, as electrodes. The great point in setting it
up is to be sure that no acid runs from one disc of flannel to the next
over the outside of the plates, as this would create a short circuit.
The plates are best compound, being made up of a zinc and a copper plate
soldered together. They may, however, be separate, and merely laid one
on the other. In such case great care must be taken to admit no acid
between them.
Volta's pile is no longer used, except occasionally. Trouvé's blotting
paper battery (see Battery, Trouvé's) is a relic of it, and the same is
to be said for Zamboni's dry pile.
It rapidly polarizes, the flannel retains but little acid, so that it is
soon spent, and it is very troublesome to set up. Great care must be
taken to have the cloth discs thoroughly saturated, and wrung out to
avoid short circuiting by squeezing out of the acid.
Battery, D'Arsonval's.
A battery of the Bunsen type, differing therefrom in the solutions. As
excitant in which the zinc electrode is immersed, the following solution
is used:
Water, 20 volumes;
Sulphuric Acid (purified by shaking with a little olive or similar oil),
1 volume;
hydrochloric acid, 1 volume.
As polarizer in which the carbon is immersed the following is used:
Nitric acid, 1 volume;
hydrochloric acid, 1 volume;
water acidulated with 1/20th sulphuric acid, 2 volumes.
Battery, de la Rue.
A battery with zinc positive and silver negative electrode; the
depolarizer is silver chloride; the excitant common salt or ammonium
chloride. The cut shows one of its forms of construction.
The right hand portion of the cut, Fig. 42, shows the zinc perforated at
C for the connection from the next silver plate. The next to it is the
negative electrode of silver around which a mass of silver chloride is
cast in cylindrical form. A is a parchment paper cylinder with two holes
near its top, through which the silver wire of the negative electrode is
threaded, as shown in B. A solution of 23 parts ammonium chloride in
1,000 parts of water is the approved excitant. Its electro-motive force
is 1.03 volts.
The jars are closed with paraffin.
Fig. 42. DE LA RUE'S BATTERY.
63 STANDARD ELECTRICAL DICTIONARY.
Battery, Dry.
(a) A form of open circuit battery in which the solutions by a mass of
zinc oxychloride, gypsum, or by a gelatinous mass such as gelatinous
silica, or glue jelly, are made practically solid. Numbers of such have
been patented, and have met with considerable success.
(b) Zamboni's dry pile, q. v., is sometimes termed a dry battery.
Battery, Element of.
A term applied sometimes to a single plate, sometimes to the pair of
plates, positive and negative, of the single couple.
Battery, Faradic.
A term applied, not very correctly however, to apparatus for producing
medical faradic currents. It may be an induction coil with battery, or a
magneto-generator worked by hand.
Battery, Ferric Chloride.
A battery of the Bunsen type, in which a solution of perchloride of iron
(ferric chloride) is used for the depolarizing agent. A little bromine
is added with advantage. The depolarizing agent recuperates on standing,
by oxidation from the oxygen of the air.
Battery, Fuller's.
A battery of the Bunsen type. The zinc plate is short and conical, and
rests in the porous jar into which some mercury is poured. An insulated
copper wire connects with the zinc. A plate of carbon is in the outer
jar. The solutions are used as in the Bunsen battery.
Synonym--Mercury Bichromate Battery.
Battery, Gas.
(a) A battery whose action depends on the oxidation of hydrogen as its
generating factor. It was invented by Grove. Plates of platinum are
immersed in cups of dilute acid, arranged as if they were plates of zinc
and carbon, in an ordinary battery. Each plate is surrounded by a glass
tube sealed at the top. The plates are filled with acid to the tops.
Through the top the connection is made. A current from another battery
is then passed through it, decomposing the water and surrounding the
upper part of one set of plates with an atmosphere of oxygen and of the
other with hydrogen. Considerable quantities of these gasses are also
occluded by the plates. On now connecting the terminals of the battery,
it gives a current in the reverse direction of that of the charging
current.
This battery, which is experimental only, is interesting as being the
first of the storage batteries.
(b) Upward's Chlorine Battery and any battery of that type (see Battery,
Upward's,) is sometimes termed a gas battery.
64 STANDARD ELECTRICAL DICTIONARY.
Battery Gauge.
A pocket or portable galvanometer for use in testing batteries and
connections.
Battery, Gravity.
A battery of the Daniell type, in which the porous cup is suppressed and
the separation of the fluids is secured by their difference in specific
gravity. A great many forms have been devised, varying only in details.
The copper plate, which is sometimes disc shaped, but in any case of
inconsiderable height, rests at the bottom of the jar. Near the top the
zinc plate, also flat or of slight depth, is supported. As exciting
liquid a strong solution of copper sulphate lies at the bottom of the
jar. This is overlaid by a solution of zinc sulphate, or sodium
sulphate, which must be of considerably less specific gravity than that
of the copper sulphate solution. In charging the jar one-tenth of a
saturated solution of zinc sulphate mixed with water is sometimes used
as the upper fluid. This may be first added so as to half fill the jar.
The strong solution of copper sulphate may then be added with a syphon
or syringe underneath the other so as to raise it up. From time to time
copper sulphate in crystals are dropped into the jar. They sink to the
bottom and maintain the copper sulphate solution in a state of
saturation.
Fig. 43. GRAVITY BATTERY OF THE TROUVÉ-CALLAUD TYPE.
If the battery is left on open circuit the liquids diffuse, and metallic
copper precipitates upon the zincs. This impairs its efficiency and
creates local action. As long as the battery is kept at work on closed
circuit work but little deposition, comparatively speaking, occurs.
From time to time, in any case, the zinc plates are removed and scraped,
so as to remove the copper which inevitably forms on their surface. Care
must be taken that the zinc sulphate solution, which is constantly
increasing in strength, does not get so strong as to become of as high
specific gravity as the copper sulphate solution. From time to time some
of the upper solution is therefore removed with a syphon or syringe and
replaced with water. An areometer is useful in running this battery.
65 STANDARD ELECTRICAL DICTIONARY.
Battery, Grenet.
A plunge battery with zinc positive and carbon negative electrodes.
Electropoion or other chromic acid or bichromate solution is used as
depolarizer and excitant. The zinc plate alone is plunged into and
withdrawn from the solution.
Fig. 44. GRENET'S BATTERY.
Fig. 45. GROVE'S BATTERY.
Battery, Grove's.
A two fluid galvanic battery. A porous cup has within it a riband of
platinum, which is the negative plate; amalgamated zinc in the outer jar
is the positive plate. Dilute sulphuric acid (10 per cent. solution) is
placed in the outer jar, and strong nitric acid (40° B.) as a
depolarizer in the porous cups. Its E. M. F. is 1.96 volts.
It is objectionable, as it gives off corrosive nitrous fumes. These are
produced by the oxidation of the nascent hydrogen by the nitric acid, by
the following reaction:
3 H + H N O3 = 2 H2 O + N O. There are other reactions, one of which
results in the formation of ammonia by the reduction of the nitric acid
radical by the hydrogen. Ammonium can be detected in the spent liquids.
66 STANDARD ELECTRICAL DICTIONARY.
Battery, Hydrochloric Acid.
A battery in which hydrochloric acid is used as the excitant. Many
attempts have been made to use this acid in batteries, but the volatile
nature of the acid causes the production of so much odor with corrosive
fumes that it has never come into use.
Battery, Lead Chloride.
A battery of the lead sulphate type in which lead chloride is the
depolarizer. It has had no extended use.
Battery, Lead Sulphate.
A battery similar to Marié Davy's battery or the gravity battery, but
using lead sulphate as depolarizer and excitant. Lead, copper or tin is
the material of the negative plate. Becquerel used the lead sulphate as
a solid cylindrical mass surrounding a lead rod 1/5 to 1/4 inch in
diameter. One part of common salt may be mixed with 5 parts of the lead
sulphate. The electro-motive force is about 0.5 volt. The resistance is
very high.
Battery, Leclanché.
An open circuit battery with porous cup. In the outer jar is a zinc rod;
a carbon plate is placed in the porous cup. The latter is packed with a
mixture of clean powdered manganese binoxide as depolarizer, and
graphite in equal volumes. A strong solution of ammonium chloride (sal
ammoniac) is placed in the outer jar. It is only used on open circuit
work. Its electromotive force is 1.48 volts, when not polarized.
The reaction is supposed to be about the following:
2 N H4 Cl + 2 Mn O2 + Zn = Zn Cl2 + 2 N H3 + H2 0 + M2 O3
The battery rapidly weakens on open circuit, but quickly recuperates.
There is another form of this battery, termed the agglomerate battery.
(See Battery, Leclanché Agglomerate.)
Fig. 46. LECLANCHÉ BATTERY.
Battery, Leclanché Agglomerate.
A form of the Leclanché in which the porous jar is suppressed. Cakes
made of a mixture of carbon, 52 parts; manganese binoxide, 40 parts; gum
lac, 5 parts; potassium bisulphate, 3 parts, compressed at 300
atmospheres, at a temperature of 100° C. (212° F.), are fastened by
India rubber bands or otherwise against the carbon plate. These
constitute the depolarizer. Various shapes are given the carbon and
depolarizing agglomerates.
Battery, Local.
A battery supplying a local circuit (see Circuit. Local). The current is
governed by the relay situated on the main line and operated by its
current.
Battery, Main.
The battery used in operating the main line. It is usually applied to
telegraphy. Its function is then to supply current for working relays,
which in turn actuate the local circuits.
Main and local circuits and batteries are also used in the automatic
block system of railroad signalling.
67 STANDARD ELECTRICAL DICTIONARY.
Battery, Marié Davy's.
A two fluid porous cup battery with carbon negative plate, zinc positive
plate, and mercury sulphate, a nearly insoluble salt, as depolarizer and
excitant. Mercurous or mercuric sulphates have been used in it. Its
electromotive force is 1.5 volts. The local action and waste, owing to
the slight solubility of the mercury compounds, is very slight. If used
on close circuit it becomes polarized. It is also subject under extreme
circumstances to reversal of polarity, zinc becoming deposited upon the
carbon, and there forming a positive electrode.
In using the cells in series the level of liquid in all must be the
same, otherwise the cell in which it is lowest will become polarized and
exhausted.
Modifications of this battery on the lines of the gravity battery have
been constructed.
Synonym--Sulphate of Mercury Battery.
Battery, Maynooth's.
A battery of the Bunsen type, with cast iron negative plate. The iron
takes the passive form and is not attacked.
Battery, Medical.
A term applied very indiscriminately to medical current generators, and
to medical induction coils, or to any source of electricity, static or
current, for medical application.
68 STANDARD ELECTRICAL DICTIONARY.
Battery, Meidinger's.
A variety of Daniell cell of the gravity type. The plates are
cylindrical. The zinc plate lies against the upper walls of the vessel.
The copper plate of smaller diameter rests on the bottom. A large tube,
with an aperture in its bottom, is supported in the centre and is
charged with copper sulphate crystals. The cup is filled with a dilute
solution of Epsom salts (magnesium sulphate) or with dilute sulphuric
acid.
Battery Mud.
A deposit of mud-like character which forms in gravity batteries and
which consists of metallic copper precipitated by the zinc. It indicates
wasteful action.
Battery, Multiple-connected.
A battery connected in parallel, all the positive plates being connected
to one electrode, and all the negative to another.
Battery, Nitric Acid.
A battery in which nitric acid is used as the excitant. Owing to its
cost and volatility this acid has been but little used in batteries,
other than as a depolarizer. In Grove's battery (see Battery, Grove's)
it has been thus used.
Battery of Dynamos.
A number of dynamos may be arranged to supply the same circuit. They are
then sometimes termed as above, a Dynamo Battery. They may be arranged
in series or in parallel or otherwise combined.
Battery of Leyden Jars.
To produce the quantity effect of a single large Leyden jar with a
number of small ones they are often connected in parallel and termed a
battery. In such case the inner coatings are all connected by regular
bar conductors, and the outside coatings are also all in connection.
They are conveniently placed in a box or deep tray whose inner surface
is lined with tinfoil, with an outside connection for grounding, etc.
The cascade, q. v., arrangement is not so generally termed a battery.
Battery, Open Circuit.
A battery adapted for use in open circuit work. Its main requirement is
that it shall not run down, or exhaust itself when left on open circuit.
The Leclanché battery is very extensively used for this work. Its action
is typical of that of most open circuit batteries. It is without any
action on open circuit. It is very quickly exhausted on closed circuit,
but recuperates or depolarizes quite soon when on open circuit. It is
always in condition for a momentary connection, but useless for steady
work.
Battery, Oxide of Copper.
A battery with zinc positive and iron negative electrodes. The excitant
is a 30 or 40 per cent. solution of sodium or potassium hydrate (caustic
soda or caustic potash). The depolarizer is copper oxide. In action the
copper is gradually reduced to the metallic state. The iron element is
often the containing vessel. The battery is practically inactive on open
circuit.
Its electro-motive force varies from .75 to .90 volt. To prevent the
formation of sodium or potassium carbonate the cell should be closed, or
else the liquid should be covered with mineral oil.
Synonyms--Lalande & Chaperon Battery--Lalande-Edison Battery.
69 STANDARD ELECTRICAL DICTIONARY.
Battery, Peroxide of Lead.
A battery in which peroxide of lead (lead binoxide) is the depolarizer.
It is a sort of predecessor of the present secondary battery.
Battery, Platinized Carbon.
A modification of Smee's battery, in which platinized carbon is used for
the negative plates. Before polarization the E. M. F. is equal to that
of Smee's battery. Polarization reduces its electro-motive force
one-half.
Battery, Plunge.
A battery whose plates are mounted so as to be immersed in the battery
cups or cells, when the battery is to be used, and withdrawn and
supported out of the cups when not in use. The object is to prevent
wasting of the plates by standing in the solution. It is a construction
generally used with sulphuric acid--chromic acid solution and
amalgamated zinc and carbon plates.
Battery, Pneumatic.
A battery arranged to have air blown through the solution to assist
diffusion and depolarization. It is a construction applied to chromic
acid or bichromate batteries.
Battery, Primary.
A battery in which the current is supplied by the solution of one of the
plates by the solution. The term distinguishes it from a secondary or
storage battery.
Battery, Pulvermacher's Electro-Medical.
In this battery, the electrodes were zinc and copper wires wound upon
small pieces of wood. Dilute vinegar was used as the excitant, because
it could be found in every household. Formerly the battery had great
success. It is now little used.
Battery, Sal Ammoniac.
Batteries in which a solution of ammonium chloride is the excitant; they
are very extensively used on open circuit work. (See Battery,
Leclanché.)
The crystals formed in these batteries have been analyzed and found to
consist of ammonium zinc chloride, 3 Zn Cl2, 8 N H3, 4 H20.
Battery, Salt, or Sea Salt.
Batteries in which a solution of sodium chloride or common salt is the
excitant, have been largely used, especially for telegraphic purposes.
The Swiss telegraphs use a carbon-zinc combination with salt and water
as the excitant. The batteries are sometimes mounted as plunge
batteries. They are exhausted by short circuiting after some hours, but
recuperate on standing. The zinc is not amalgamated.
70 STANDARD ELECTRICAL DICTIONARY.
Battery, Sand.
A battery whose cells are charged with sand saturated with dilute acid.
It prevents spilling of acid. It is now practically obsolete.
Fig. 47. SECONDARY BATTERY.
Battery, Secondary.
A voltaic battery whose positive and negative electrodes are formed or
deposited by a current from a separate source of electricity by
electrolysis. On disconnection the battery is ready to yield a current,
in the reverse direction of that of the charging current. The usual type
has lead plates on one of which lead binoxide and on the other of which
spongy lead is formed. The lead binoxide seems to be the negative
element, and it also acts as the depolarizer. The spongy lead is the
positive electrode. The solution is dilute sulphuric acid of specific
gravity 1.17. The action consists first in the oxidation of the spongy
lead. The hydrogen set free by the reaction, and which by electrolytic
transfer goes to the other plate, reduces the lead binoxide to
protoxide. The sulphuric acid then attacks the oxides and converts the
oxides into sulphates.
The charging process consists in sending a current in the reverse
direction through the battery. If there are several cells they are
arranged in series, so that each one receives the same intensity of
current. An electrolytic decomposition takes place, the lead sulphate on
one plate is reduced to metallic lead, and that on the other plate is
oxidized to lead binoxide. It is then ready for use.
71 STANDARD ELECTRICAL DICTIONARY.
The plates in a lead plate battery are of very large area per cell, and
are placed close together. Sometimes, as in Planté's battery, large flat
plates are laid together with a separating insulator between them, and
are then rolled into a spiral. Sometimes, the most usual arrangement,
the plates are in sets, the positive and negative ones alternating, and
each cell containing a number of plates.
To secure a good quantity of active material, the plates are sometimes
perforated, and the perforations are filled with oxide of lead. This
gives a good depth of material for the charging current to act on, and
avoids the necessity for a tedious "forming," q. v.
The electro-motive force of such a battery per cell is 2 volts. Its
resistance may only be one or two-hundredths of an ohm. An intense
current of many amperes can be supplied by it, but to avoid injuring the
cell a current far less than the maximum is taken from it.
To charge it, a slightly greater electro-motive force, the excess being
termed spurious voltage, is required.
Fig. 48. SIEMENS' AND HALSKE'S PAPER PULP BATTERY.
72 STANDARD ELECTRICAL DICTIONARY.
Battery, Secondary, Plante's.
Plante's secondary battery is one of the earlier forms of storage
battery, but has had much success. Two lead plates, large in area and
close together but not touching, are "formed," by exposure to an
electrolyzing current of electricity in one direction, while they are
immersed in dilute sulphuric acid. This converts the surface of one
plate into binoxide. The cell is then allowed to discharge itself almost
completely, when the charging current is again turned on. This process
is repeated over and over again, until the surfaces of the plates are
considerably attacked, one plate, however, being maintained in a state
of oxidation. After a few days of this operation a period of rest is
allowed between the reversals, which sets up a local action on the
oxidized plate, between the metallic lead of the plate, and its coating
of binoxide. This causes the lead to be attacked, under the influence of
the local couple, and sulphate of lead is formed, which, ultimately, by
the charging current is converted into peroxide. These operations
produce an exceedingly good battery. The process described is termed
forming.
The plates separated by strips of insulating material are generally
wound into a double spiral.
Battery, Siemens' and Halske's.
A Daniell battery of peculiar shape. The copper, C, is at the bottom of
the glass jar, A. The inner jar, K, has the form of a bell, and supports
a mass of paper pulp, which is dampened with sulphuric acid. The zinc,
Z, rests on top of the mass of pulp. The battery is very durable, but of
high resistance.
Battery, Sir William Thomson's.
A form of Daniell battery, of the gravity type. The receptacles are
shallow wooden trays lined with lead. A thin plate of copper rests on
the bottom. The zinc plate is of gridiron shape, and rests on wooden
blocks which support it in a horizontal position above the copper. One
tray is placed on top of the other, the upper tray resting on the
corners of the zinc plate which rise above the level of the top of the
flat vessel. Thus connection is assured without wires or binding posts.
It is charged like a gravity battery. The density of the zinc sulphate
solution should be between 1.10 and 1.30. The circuit must be kept
closed to prevent deposition of metallic copper on the zinc. The entire
disposition of the battery is designed to reduce resistance.
Battery, Skrivanow.
A pocket battery of the De la Rue type, with a solution of 75 parts
caustic potash in 100 parts of water as the excitant. The silver
chloride is contained in a parchment paper receptacle. Its
electro-motive force is 1.45 to 1.5 volts.
Battery, Smee's.
A single fluid combination, with zinc positive plate, and a plate of
silver, coated with platinum black, for the negative plate. The finely
divided platinum affords a surface from which the hydrogen bubbles
instantly detach themselves, thus preventing polarization. The liquid is
a mixture of one part sulphuric acid to seven parts of water. For the
negative plate silver-plated copper, coated with platinum black, is
used. Electromotive force, .47 volt.
Fig. 49. SMEE'S BATTERY.
73 STANDARD ELECTRICAL DICTIONARY.
Fig. 50. SPIRAL BATTERY, OR HARE'S DEFLAGRATOR.
Battery, Spiral.
A battery whose plates of thin zinc and copper are wound into a spiral
so as to be very close, but not touching. Dilute sulphuric acid is the
excitant. It is now practically obsolete.
Synonyms--Calorimeter--Hare's Deflagrator.
Battery, Split.
A battery of a number of voltaic cells, connected in series, with their
central portion grounded or connected to earth. This gives the ends of
opposite potentials from the earth, and of difference therefrom equal to
the product of one-half of the number of cells employed, multiplied by
their individual voltage.
Battery Solutions, Chromic Acid.
A number of formulae have been proposed for these solutions. (See
Electropoion Fluid--Kookogey's Solution--Poggendorff's Solution--
Trouvé's Solution--Delaurier's Solution--Chutaux's Solution--Dronier's
Salt--Tissandier's Solution.)
Battery, Trough.
A battery whose elements are contained in a trough, which is divided by
cross-partitions so as to represent cups. A favorite wood for the trough
is teak, which is divided by glass or slate partitions. Marine glue or
other form of cement is used to make the joints tight. For porous cup
divisions plates of porous porcelain or pottery are placed across,
alternating with the impervious slate partitions.
Battery, Trouvé's Blotting Paper.
A battery of the Daniell type in which the solutions are retained by
blotting paper. A considerable thickness of blotting paper lies between
the two plates. The upper half of the thickness of the blotting paper is
saturated with a solution of zinc sulphate, on which the zinc plate
rests.
The lower half of the paper is saturated with copper sulphate solution,
and this rests upon the copper plate.
Fig. 51. TROUVÉ'S BLOTTING PAPER BATTERY.
74 STANDARD ELECTRICAL DICTIONARY.
Battery, Tyer's.
A modification, as regards the positive element, of Smee's battery, q.
v. The bottom of the battery jar contains a quantity of mercury in which
pieces of zinc are thrown, and this constitutes the positive element.
A ball of zinc at the end of an insulated copper wire affords the
connection with the zinc and mercury. Its great advantage is that the
smallest scraps of zinc can be used in it, by being dropped into the
mercury. The negative plate is platinized silver; the exciting liquid,
dilute sulphuric acid.
Fig. 52. TYER'S BATTERY.
75 STANDARD ELECTRICAL DICTIONARY.
Fig. 53. SECTION OF UPWARD'S BATTERY.
Fig. 54. ELEVATION OF UPWARD'S BATTERY.
Battery, Upward's.
A primary voltaic cell, the invention of A. Renée Upward. Referring to
the cuts, the positive plate. Z, is of cast zinc; it is immersed in
water, in a porous cup, B. Outside of the porous cup and contained in
the battery jar are two carbon plates, C, C, connected together. The
rest of the space between the porous cup and battery jar is packed with
crushed carbon, and the top is cemented. Chlorine gas is led by a pipe,
D, into the outer cell. It diffuses through the fine carbon, dissolves
in the water, and so finds its way to the zinc, which it attacks,
directly combining therewith, and forming zinc chloride (Zn + 2 Cl = Zn
Cl 2). Such of the chlorine as is not absorbed finds its way by an outlet
tube, E, to the next cell. Arrangements are provided for generating
chlorine gas as required. The high specific gravity of the gas is
utilized in regulating its distribution through the cells. The
electro-motive force of the cell is 2.1 volts. A cell 11.5 by 5.5 inches
and 12.5 inches deep has a resistance of 0.2 ohm.
An overflow pipe, F, with faucet, T, is supplied to withdraw the
solution of zinc chloride as it accumulates.
76 STANDARD ELECTRICAL DICTIONARY.
Battery, Varley's.
A Daniell battery of the Siemens' and Halske's type (see Battery,
Siemens' and Halske's), in which zinc oxide is substituted for the paper
pulp of the other battery. It has been very little used.
Battery, Volta's.
The original acid battery. It has a negative electrode of copper, a
positive electrode of zinc; the excitant is sulphuric acid diluted with
sixteen times its volume of water. It rapidly polarizes, and is very
little used.
Battery, Voltaic or Galvanic.
An apparatus for converting chemical energy directly into electric
energy. This is as broad a definition as can well be given. The general
conception of a battery includes the action of electrolysis, a solution
in the battery acting upon one of two conducting electrodes immersed in
such fluid, which dissolves one of them only, or one more than the
other. The best way to obtain a fundamental idea of a battery is to
start with the simplest. Dilute sulphuric acid dissolves neither pure
zinc nor copper. But it has a far stronger affinity for the first named
metal. If now we immerse in dilute acid two plates, one of pure zinc,
and one of copper, no action will be discernible. But if the plates are
brought in contact with each other a stream of bubbles of hydrogen gas
will escape from the surface of the copper and the zinc will dissolve.
By applying proper tests and deductions it will be found that the copper
and zinc are being constantly charged with opposite electricities, and
that these are constantly recombining. This recombination produces what
is known as an electric current.
To constitute a battery the zinc and copper plates must be connected
outside of the solution. This connection need not be immediate. Any
conductor which touches both plates will bring about the action, and the
current will pass through it.
The easiest way to picture the action of a battery is to accept the
doctrine of contact action. In the battery the molecules of water are
pulled apart. The hydrogen molecules go to the copper, the oxygen
molecules go to the zinc, each one, leaving its contact with the other,
comes off charged with opposite electricity. This charges the plates,
and the continuous supply of charge and its continuous discharge
establishes the current.
The accumulation of hydrogen acts to stop the action by polarization.
Its own affinity for oxygen acts against or in opposition to the
affinity of the zinc for the same element, and so cuts down the action.
A depolarizer of some kind is used in acid batteries for this reason. As
such depolarizer has only to act upon one plate, in most batteries it is
usual to surround such plate only, as far as it is possible, with the
depolarizer. The solution which dissolves the zinc is termed the
excitant or exciting solution.
To this concrete notion of a voltaic battery the different modifications
described here may be referred. Zinc, it will be seen, forms the almost
universally used dissolved plate; carbon or copper forms the most usual
undissolved plate; sulphuric acid in one form or another is the most
usual excitant.
The solution in a voltaic battery is electrolyzed (see Electrolysis).
Hence the solutions must be electrolytes. The sulphuric acid and other
ingredients play a secondary role as imparting to the battery fluids
this characteristic.
It is not necessary to have electrodes of different substances, the same
metal maybe used for both if they are immersed in different solutions
which act differentially upon them, or which act with more energy on one
than on the other. Such are only of theoretical interest.
77 STANDARD ELECTRICAL DICTIONARY.
Battery, Water.
A voltaic battery, whose exciting fluid is water. They are used for
charging quadrant electrometer needles and similar purposes. They
polarize very quickly and are of high resistance. Hence very small
plates in large number can be used without impairing their advantage.
Rowland's water battery dispenses with cups and uses capillarity
instead. The zinc and platinum or copper plates of a couple are placed
very close together, while the couples are more distant. On dipping into
water each couple picks up and retains by capillarity a little water
between its plates, which forms the exciting fluid. Many hundred couples
can be mounted on a board, and the whole is charged by dipping into
water and at once removing therefrom. It then develops its full
potential difference.
Fig. 55. SECTION OF WOLLASTON BATTERY.
Fig. 56. PLATES OF WOLLASTON'S BATTERY.
78 STANDARD ELECTRICAL DICTIONARY.
Battery, Wollaston.
The original plunge battery is attributed to Wollaston. He also invented
the battery known by his name, having the disposition shown in the cut,
of zinc Z, surrounded by a thin sheet of copper C; o, o', o", are the
terminals and B, B, the battery jars. Dilute sulphuric acid is used for
exciting fluid.
B. A. U.
Abbreviation for British Association unit, referring generally to the B.
A. unit of resistance.
B. A. Unit of Resistance.
The original ohm used under that name previous to 1884. The Paris
committee of that year recommended as a practical unit what is known as
the legal ohm. (See Ohm, Legal.)
1 Legal Ohm = 1.0112 B. A. Units of Resistance.
1 B. A. Unit of Resistance = .9889 Legal Ohms.
1 B. A. Unit of Resistance = .98651E9 C. G. S. units.
B. E. adj.
British Engineering, a qualification of a set of units, the B. E. units,
having for base the foot and pound. The term is but little used.
Beaumé Hydrometer.
A hydrometer graduated on the following principle:
The zero point corresponds to the specific gravity of water for liquids
heavier than water. A solution of 15 parts of salt in 85 parts of water
corresponds in specific gravity to 15° B., and between that and zero
fifteen equal degrees are laid out. The degrees are carried down below
this point.
The zero points for liquids lighter than water correspond to the
specific gravity of a solution of 10 parts of salt in 90 parts of water.
The specific gravity of water is taken as 10° B. This gives ten degrees
which are continued up the scale.
Becquerel's Laws of Thermoelectricity.
These are stated under the heads, Law of Intermediate Metals and Law of
Successive Temperatures, q. v.
Bed Piece.
In a dynamo or motor the frame carrying it, including often the
standards in which the armature shaft is journaled, and often the yoke
or even entire field magnet core.
Bell, Automatic Electric.
A bell which rings as long as the circuit is closed, having a circuit
breaker operated by its own motion. (See Bell, Electric.)
Synonyms--Trembling Bell--Vibrating Bell.
Bell, Call.
A bell operated by electricity, designed to call attention, as to a
telephone or telegraphic receiver. (See Bell, Electric.)
79 STANDARD ELECTRICAL DICTIONARY.
Bell Call.
A calling device for attracting the attention of any one, consisting of
some type of electric bell.
Bell, Circular.
A gong-shaped bell, whose clapper and general mechanism is within its
cavity or behind it.
Bell, Differentially Wound.
An electric bell, whose magnet is wound differentially so as to prevent
sparking.
Fig 57. AUTOMATIC ELECTRIC BELL.
Bell, Electric.
A bell rung by electricity. Generally it is worked by a current exciting
an electro-magnet, attracting or releasing an armature which is attached
to the vibrating or pivoted tongue of the bell. It may be worked by a
distant switch or press-button, q. v., ringing once for each movement of
the distant switch, etc., or it may be of the vibrating bell type as
shown in the cut. When the current is turned on in this case it attracts
the armature. As this moves towards the poles of the magnet it breaks
the circuit by drawing the contact spring, q. v., away from the contact
point, q. v. This opens the circuit, to whose continuity the contact of
these two parts is essential. The hammer, however, by its momentum
strikes the bell and at once springs back. This again makes the contact
and the hammer is reattracted. This action continues as long as the
circuit is closed at any distant point to which it may be carried. The
ordinary vibrating bell is a typical automatic circuit breaker, q. v.,
this type keeping up the ringing as long as the circuit is closed. Other
bells have no electric contact and simply ring once every time the
circuit is closed. Others worked by an alternating current ring once for
each change of direction of current.
80 STANDARD ELECTRICAL DICTIONARY.
Bell, Electro-mechanical.
A bell which has its striking train operated by a spring or descending
weight, and which train is thrown into action by the release of a detent
or equivalent action by the closing of an electric circuit. It rings for
any given time after being started.
Bell, Indicating.
A bell which by drop-shutter or other indicator connected in circuit
with it, indicates its number or other designation of its call.
Bell, Magneto.
An electric bell operated by the alternating current from a magneto
generator. It has a polarized armature and no circuit breaker. The
armature is attracted first in one direction and then in the other, as
the current alternates and reverses the polarity of the electro-magnet.
Bell, Relay.
A bell operated by a relay circuit.
Bias.
In polarized relay the adjustment of the tongue to lie normally against
one or the other contact. (See Relay, Polarized.)
81 STANDARD ELECTRICAL DICTIONARY.
Fig. 58. RESISTANCE COILS SHOWING BIFILAR WINDING.
Bifilar Winding.
The method followed in winding resistance coils to prevent them from
creating fields of force. The wire is doubled, and the doubled wire
starting with the bend or bight is wound into a coil. The current going
in opposite senses in the two lays of the winding produces no field of
force.
Binary Compound.
A chemical compound whose molecule contains only two elements, such as
water (H2 0), lead oxide (Pb 0), and many others.
Binding.
In a dynamo or motor armature the wire wound around the coils to secure
them in place and prevent their disturbance by centrifugal action.
Fig. 59. DOUBLE BINDING POST.
Fig. 60. BINDING POST, ENGLISH PATTERN.
FIG. 61. WOOD SCREW BINDING POST.
Binding Posts or Screws.
Arrangements for receiving the loose end of a wire of an electric
circuit, and securing such end by a screw. Several constructions are
used, as shown here. Sometimes the wire is passed through a hole, and a
screw tapped in at right angles to the hole is screwed down upon the
wire. Sometimes the wire is clamped between two shoulders, one on the
screw, the other on the post. The screw is often a flat-headed thumb
screw or has a milled edge. Sometimes the screw has a slot and is turned
by a screw-driver.
Several openings are often provided in the same post for different
wires.
Binnacle.
The case containing a mariner's compass on shipboard. It is enclosed
completely; it has a glass side or window through which the compass can
be seen, and is provided with one or two lamps arranged to light the
card, while showing as little light as possible outside.
82 STANDARD ELECTRICAL DICTIONARY.
Bioscopy, Electric.
The diagnosis of life and death by the action of the animal system when
subjected to an electric current or electrification.
Bismuth.
A metal, one of the elements, atomic weight, 210 ; equivalent, 70;
valency, 3; specific gravity, 9.9. It is a conductor of electricity.
Relative Resistance, compressed, (silver = 1) 87.23
Specific Resistance, 131.2 microhms
Resistance of a wire
(a) 1 foot long, weighing 1 grain, 18.44 ohms
(b) 1 foot long, 1/1000 inch thick, 789.3 "
(c) 1 meter long, weighing 1 gram, 12.88 "
(d) 1 meter long, 1 millimeter thick, 1.670 "
Resistance of a 1-inch cube 51.65 microhms
Electro chemical equivalent, .7350
(Hydrogen = .0105)
(See Thermo-electric Series.)
FIGS. 62, 63. INCANDESCENT WIRE FUSE. ABEL'S PATENT.
FIG 64. VON EBNER'S FRICTIONAL ELECTRIC MACHINE FOR
EXPLODING ELECTRIC FUSES OR DETONATORS.
Bi-telephone.
A pair of telephones arranged with a curved connecting arm or spring, so
that they can be simultaneously applied to both ears. They are
self-retaining, staying in position without the use of the hands.
83 STANDARD ELECTRICAL DICTIONARY.
Blasting, Electric.
The ignition of blasting charges of powder or high explosives by the
electric spark, or by the ignition to incandescence (red or white heat)
of a thin wire immersed in or surrounded by powder. Special influence or
frictional electric machines or induction coils are used to produce
sparks, if that method of ignition is employed. For the incandescent
wire a hand magneto is very generally employed. (See Fuse, Electric.)
The cuts, Figs. 62 and 63, show one form of incandescent wire fuse. The
large wires are secured to the capsule, so that no strand can come upon
the small wire within the cavity.
The cut, Fig. 64, shows a frictional electric machine for igniting spark
fuses.
Bleaching, Electric.
Bleaching by agents produced or made available by the direct action of
electricity. Thus if a current under proper conditions is sent through a
solution of common salt (sodium chloride), the electrodes being close
together, the salt is decomposed, chlorine going to one pole and sodium
hydrate to the other. The two substances react upon each other and
combine, forming sodium hypochlorite, which bleaches the tissue immersed
in its solution.
Block System.
A system of signalling on railroads. The essence of the system consists
in having signal posts or stations all along the road at distances
depending on the traffic. The space between each two signal posts is
termed a block. From the signal posts the trains in day time are
signalled by wooden arms termed semaphores, and at night by lanterns.
The arms may be moved by hand or by automatic mechanism depending in
part on electricity for carrying out its functions. Thus in the
Westinghouse system the semaphores are moved by pneumatic cylinders and
pistons, whose air valves are opened and shut by the action of solenoid
magnets, q. v. The current of these magnets is short circuited by
passing trains, so as to let the valves close as the train passes the
signal post. The block system causes the semaphore to be set at "danger"
or "caution," as the train enters the next block. Then the following
train is not allowed to enter the block until the safety signal is
shown. The Westinghouse system provides for two semaphores on a post,
one indicating "danger" as long as the train is on the next block; the
other indicating "caution" as long as the train is on the next two
blocks. The rails form part of the circuit, their joints being bridged
by copper wire throughout the block, and being insulated where the
blocks meet.
Block Wire.
In the block system a wire connecting adjacent block-signal towers or
semaphore poles.
Blow-pipe.
A name sometimes given to an electric experiment illustrating the
repulsion of electrified air particles from a point held at high
relative potential. A metallic point, placed on the prime conductor of
an electric friction or influence machine, becomes highly electrified,
and the air becoming excited is repelled and acts upon the candle flame.
If the candle is placed on the conductor and a point held towards it the
repulsion is still away from the point.
84 STANDARD ELECTRICAL DICTIONARY.
Blow-pipe, Electric Arc.
A name sometimes given to devices for using the voltaic arc to produce
local heating effects. The directive action of the magnet may be used to
force out the arc like a blow-pipe flame, or a blast of air may be
directly applied for the same purpose.
Blue-stone.
A trade name for crystallized copper sulphate, used in Daniell's and
gravity batteries.
Boat, Electric.
A boat propelled by electricity. The electricity drives a motor which
actuates a screw propeller. The current is generally supplied by a
storage battery. When used on rivers charging stations are established
at proper places. When the boat is used as a tender or launch for a
steam ship, such as a war-vessel, the battery is charged by a plant on
board the ship. From their noiselessness electric boats are peculiarly
available for nocturnal torpedo operations, and the universal equipment
of modern war-ships with electric lightning and power plants makes their
use possible at all points. This type is often termed an electric
launch, and most or all electric boats fall under this category.
Bobbins.
A spool of wood or other material wound with insulated wire. In a
tangent galvanometer the bobbin becomes a ring, with a channel to
receive the winding. As the ring is not infinitely large compared to the
needle the tangent law is not absolutely fulfilled. It is most
accurately fulfilled (S. P. Thomson) when the depth of the groove or
channel in the radial direction bears to the breadth in the axial
direction the ratio of square root of 3 to the square root of 2 or
approximately 11 : 9
Body Protector.
A metallic short circuit connected with the wrists and lower legs of the
human body, so that if by accident an active circuit is grounded by the
hands and body of the workman wearing it, most of the current will pass
through the wire conductors, thus avoiding the vital organs of the body.
Boiler Feed, Electric.
An apparatus by which an electric current acting on an electro-magnet,
or other equivalent device, opens the water supply when the water level
in a boiler sinks too low, and cuts off the water supply as the water
level rises.
Boiling.
In secondary batteries the escape of hydrogen and oxygen gas when the
battery is charged. The bubbling of the escaping gases produces the
effect of boiling.
85 STANDARD ELECTRICAL DICTIONARY.
Boll.
An absolute, or c. g. s., unit of momentum; a gram moving at the rate of
one centimeter per second; a gram-kine (see Kine); a unit proposed by
the British Association.
Bolometer.
An apparatus for detecting small amounts of radiant energy (radiant
heat, so called). A coil suspended by a fine wire or filament so as to
be free to rotate under the effect of force is made up of two parallel
and equal wires, insulated from each other, but connected so that
parallel currents sent through them go in opposite direction through
each. This coil is hung in a strong electro-magnetic field produced by a
large coil surrounding it. When a current passes through the suspended
coil no effect will follow, because the oppositely wound portions
counteract each other exactly. In the circuit with one half of the
suspended coil is an exceedingly thin strip of platinum wire. The other
half of the coil has no strips. Both halves unite after leaving the
coil. If now the strip of platinum is heated its conductivity is
affected and its half of the coil receives less current than the other
half. This disturbs the balance and the coil swings through a small arc.
This apparatus may be made very sensitive, so that an increase of
temperature of 1/1400º F., 9/70000°C. (1/14000º F.) will be perceptible.
Another construction takes the form of a Wheatstone Bridge, q. v., in
whose arms are introduced resistances consisting of bands of iron, .5
Millimeter wide (.02 inches), .004 millimeter (.00016 inch) thick, and
folded on themselves 14 times so as to make a rectangular grating, 17 x
12 millimeters (.68 x .48 inch). The least difference of heat applied to
the grating affects the galvanometer.
Synonym-Thermic Balance.
Boreal Pole.
The south pointing pole of the magnet. (See Austral Pole.)
Bot.
A colloquial expression for the English Board of Trade unit of
Electrical Supply. It is formed of the initials of the words "Board of
Trade." (See Unit, Board of Trade.)
Box Bridge.
A constriction of Wheatstone's Bridge in which the necessary resistance
coils are contained in a single box with plugs for throwing the coils in
and out of circuit, and connections to bring the coils into the
different arms of the system. The cut shows a box bridge. Connections
for the galvanometer, battery wires, and terminals of the unknown
resistance are provided, by which its resistances and the connections
are brought into the exact relations indicated in the conventional
diagram of Wheatstone's bridge. (See Wheatstone's Bridge.)
Referring to the cut, the battery wire, say from the zinc plate,
connects at A1, thereby reaching A, its true connecting point. To B1 one
end of the galvanometer circuit or lead is attached, thereby reaching B,
its true connecting point. To C are connected the other end from the
galvanometer and one end of the unknown resistance. The other end of the
unknown resistance, and the other end of the battery wire, in this case
from the carbon plate, connect to D. At G is an infinity plug, as it is
called. When out it breaks the circuit.
In use after the connections are made the key is depressed and the
galvanometer observed. The resistance is changed until no action of the
galvanometer is produced by closing the circuit when the ratio of the
resistances of the arms gives the proportion for calculating the unknown
resistances.
Synonym--Commercial Wheatstone Bridge, or commercial form of same.
Fig. 65. TOP OF BOX BRIDGE.
86 STANDARD ELECTRICAL DICTIONARY.
Boxing the Compass.
Naming the thirty-two points of the compass in order, and in sequence to
any point called out at random. There are many exercises in the relative
sailing points and bearings that come under the same head. Thus the
direction of two given points being given by names of the compass
points, it may be required to state the number of points intervening.
Brake, Electro-magnetic.
A brake to stop a wheel from rotating. It comprises a shoe, or sometimes
a ring, which by electro-magnetic attraction is drawn against the
rotating wheel, thus preventing it from turning, or tending to bring it
to rest. (See Electro-magnet, Annular.)
Fig. 66. ELECTRIC BRAKE.
87 STANDARD ELECTRICAL DICTIONARY.
Branch.
A conductor branching from a main line. Sometimes the term is restricted
to a principal conductor, from which current is distributed.
Branch Block.
In electric wiring of buildings, a block of porcelain or other material
with grooves, holes and screws for the connection of branch wires to a
main wire. Its functions are not only to afford a basis for connecting
the wires, but also to contain safety fuses. As when a branch wire is
taken off, fuses have to be put in its line, the branch block carries
these also. One end of each fuse connects with a main wire, the other
end connects with one of the wires of the branch leader or wire.
Porcelain is a favorite material for them, as the fusing or "blowing
out" of the safety fuses cannot set it on fire.
Branch Conductor.
A parallel or shunt conductor.
Brazing, Electric.
Brazing in which the spelter is melted by means of electricity; either
current incandescence or the voltaic arc may be used. It is identical in
general with electric welding. (See Welding, Electric.)
Branding, Electric.
A system of branding in which the heat of electrically ignited or
incandescent conductors is used to produce or burn in the marks upon the
surface. For the alternating current a small transformer is connected to
or forms part of the tool.
88 STANDARD ELECTRICAL DICTIONARY.
Brassing.
The deposition of a coating of brass by electrolysis. The plating bath
contains both copper and zinc. As anode a plate of brass is used. The
operation must be constantly watched. The deposition of both metals goes
on simultaneously, so that a virtual alloy is deposited. By changing
the depth of immersion of the anode the color of the deposit is varied.
As a formula for a brassing bath the following are typical. They are
expressed in parts by weight.
(a) For iron and steel.
I.
Sodium Bisulphate, 200
Potassium Cyanide, 70 per cent., 500
Sodium Carbonate, 1,000
Water, 8,000
II.
Copper Acetate, 125
Zinc Chloride, 100
Water, 2,000
Add the second solution to the first.
(b) For zinc.
I.
Sodium Bisulphate, 700
Potassium Cyanide, 70 per cent., 1,000
Water, 20,000
II.
Copper Acetate, 350
Zinc Chloride, 350
Aqua Ammoniae, 400
Water, 5,000
Add the second solution to the first.
Use a brass anode; add more zinc to produce a greenish color; more
copper for a red color. A weak current gives a red color; a strong
current lightens the color. The battery power can be altered, a larger
or smaller anode can be used, or a copper or zinc anode can be used to
change the color of the deposit. The bath may vary from 1.036 to 1.100
sp. gr., without harm.
Break.
A point where an electric conductor is cut, broken, or opened by a
switch or other device, or simply by discontinuity of the wires.
Break-down Switch.
A switch used in the three-wire system to provide for the discontinuance
of the running of one of the dynamos.
By connecting the positive and negative bus wires to one terminal of the
active dynamo, and the neutral bus wire to the other terminal, one
dynamo will supply the current and the system operates like a two-wire
system, but can only be used for half its normal capacity.
Breaking Weight.
The weight which, applied in tension, will break a prism or cylinder, as
an electric current conductor.
89 STANDARD ELECTRICAL DICTIONARY.
Breath Figures, Electric.
If a conductor is electrified and placed upon a piece of glass, it will
electrify the glass in contact with it by conduction or discharge. On
removing the conductor the glass remains electrified. The localized
electrification is shown by breathing gently on the glass, when a
species of image of the conductor is produced by the condensed moisture.
A coin is often used for conductor.
Breeze, Electric.
A term in medical electricity, used to designate the silent or brush
discharge of high tension electricity. As an instance of its employment,
the electric head bath (see Bath, Electric Head,) may be cited. The
patient forming one electrode, being insulated and connected to one of
the conductors, the other conductor, on being brought near his person,
discharges into his body.
Bridge.
(a) A special bar of copper connecting the dynamos to the bus wire, q. v.,
in electric lighting or power stations.
(b) Wheatstone's bridge, q. v., and its many modifications, all of which
may be consulted throughout these pages.
British Association Bridge.
The type of Wheatstone bridge used by the committee of the association
in determining the B. A. ohm; the meter bridge, q. v.
Broadside Method.
A method of determining the magnetic moment of a magnet. The magnet, n,
s, under examination is fixed so that it is at right angles to the
magnetic meridian, M, R, which passes through its own center and that of
a compass needle. From the deflection of the latter the moment is
calculated.
FIG 67. BROADSIDE METHOD.
Bronzing.
In electro-plating the deposition of a mixture or virtual alloy of
copper and tin. In general manipulation it resembles the operation of
depositing gold and silver alloy, or of brassing.
For bronzing the following bath is recommended:
Prepare each by itself (a) a solution of copper phosphate and (b) a
solution of stannous chloride in a solution of sodium pyrophosphate. For
a, dissolve recently precipitated copper phosphate in concentrated
solution of sodium pyrophosphate. For b, add to a saturated solution of
sodium pyrophosphate solution of stannous chloride as long as the
precipitate which is formed dissolves. Of these two solutions add to a
solution of sodium pyrophosphate which contains about 1.75 oz. of the
salt to the quart, until the precipitate appears quickly and of the
desired color. For anodes use cast bronze plates. Sodium phosphate must
be added from time to time; if the deposit is too light add copper
solution, if too dark add tin solution. (W. T. Brannt.)
90 STANDARD ELECTRICAL DICTIONARY.
Brush.
In electric current generators and motors, the pieces of copper or other
material that bear against the cylindrical surface of the commutator are
thus termed. Many different constructions have been employed. Some have
employed little wheels or discs bearing against and rotating on the
surface of the commutator. A bundle of copper strips is often employed,
placed flatwise. Sometimes the same are used, but are placed edgewise.
Wire in bundles, soldered together at their distant ends have been
employed. Carbon brushes, which are simply rods or slabs of carbon, are
used with much success.
Synonym--Collecting Brush.
Brush, Carbon.
A brush for a dynamo or motor, which consists of a plate or rod of
carbon, held in a brush holder and pressed against the commutator
surface.
Brushes, Adjustment of.
In electric current generators and motors, the brushes which bear upon
the commutator when the machine is in action need occasional adjustment.
This is effected by shifting them until sparking between them and the
commutator is nearly or quite suppressed.
Fig. 68. BRUSH HOLDER.
Brushes, Lead of.
In a dynamo electric generator, the lead or displacement in advance of
or beyond the position at right angles to the line connecting the poles
of the field magnet, which is given the brushes. In a motor the brushes
are set back of the right angle position, or are given a negative lead.
(See Lag.)
91 STANDARD ELECTRICAL DICTIONARY.
Brush Holders.
The adjustable (generally) clutch or clamps for holding the commutator
brushes of a dynamo, which keep them in contact with the commutator, and
admit of adjustment by shifting backward and forward of the brushes to
compensate for wear. They are connected to and form part of the rocker,
q. v. By rotating the latter the brush-holders and brushes are carried
in one direction or other around the commutator, so as to vary the lead
as required.
Brush, Pilot.
A third brush, used for application to different parts of a revolving
armature commutator to determine the distribution of potential
difference between its different members. (See Curve of Distribution of
Potential in Armature.) One terminal of a volt-meter is connected to one
of the regular brushes, A, of a dynamo; the other to a third brush, p,
which is pressed against different portions of the commutator of the
dynamo. The readings of the volt-meter are plotted in a curve of
distribution of potential.
Fig. 69. PILOT BRUSH.
Brush, Rotating.
Brushes for taking off the current from dynamo commutators, or giving
current connection to motors, whose ends are in the form of rollers
which rotate like little wheels, and press against the commutator
surface.
Brush, Third.
A third brush is sometimes provided in a dynamo for regulating purposes.
Applied to a series machine it adjoins one of the regular brushes and
delivers its current to a resistance, to whose further end the regular
circuit is connected. By a sliding connection the resistance is divided
between the third brush circuit and the regular circuit, and by varying
the position of this contact regulation is obtained.
It is to be distinguished from the pilot brush used for determining the
characteristic of the commutator, although based on the same general
principles.
Fig. 70. THIRD BRUSH REGULATION.
92 STANDARD ELECTRICAL DICTIONARY.
Brush, Wire Gauze.
A collecting or commutator brush for a dynamo or motor, which brush is
made of wire gauze rolled up and compressed into shape.
Buckling.
The bending up and distortion of secondary battery plates. It is largely
due to over-exhausting the batteries. Where the E. M. F. is never
allowed to fall below 1.90 volt it is far less liable to occur.
Bug.
Any fault or trouble in the connections or working of electric
apparatus.
Bug Trap.
A connection or arrangement for overcoming a "bug." It is said that the
terms "bug" and "bug trap" originated in quadruplex telegraphy.
Bunsen Disc.
In photometry, the Bunsen Disc is a piece of paper upon whose centre a
spot is saturated with melted paraffin, or a ring of paraffined surface
surrounds an untouched central spot. If placed in such a position that
it receives an equal illumination on each side, the spot almost
disappears. It is used on the bar photometer. (See Photometer, Bar.)
Synonym--Grease Spot.
93 STANDARD ELECTRICAL DICTIONARY.
Buoy, Electric.
A buoy for use to indicate channels or dangers in harbors and elsewhere,
which carries an electric light, whose current is supplied by cable from
shore. It has been proposed to use glass tubes exhausted of air and
containing mercury, which, as moved by the waves, would produce a
luminous effect. A fifty-candle power incandescent lamp is an approved
source of light.
Burner, Electric Gas.
A gas burner arranged for the flame to be lighted by electricity. It
takes a great variety of forms. In some cases a pair of terminals are
arranged near the flame or a single terminal is placed near the metal
tip, the latter forming one of the terminals. The spark is generally
produced by an induction coil, or a spark coil. The gas may first be
turned on and the spark then passed. Sometimes the turning of the gas
cock of an individual burner makes and breaks a contact as it turns, and
thereby produces simultaneously with the turning on of the gas a spark
which lights it.
Another form is wholly automatic. A pair of electro-magnets are attached
below the base of the burner, one of which, when excited, turns on the
gas, and the other one when it is excited turns it off. At the same time
a spark is produced with the turning on of the gas so that it is
lighted. Thus, by use of a automatic burner, a distant gas burner can be
lighted by turning an electric switch. An out-door lamp may be lighted
from within a house.
The increasing use of electric incandescent lamps, lighted by the
turning of a switch, tends to displace electric gas burners. The latter
have been classified into a number of types depending on their
construction.
Burners are sometimes connected in series with leads from an induction
coil. Then the gas is turned on all at once, and a succession of sparks
passed until the gas is all lighted. The ignition is practically
instantaneous.
Button, Push.
A species of switch which is actuated by the pressure of a button. In
its normal position the button is pressed outwards by a spring, and the
circuit is open. When pressed inwards, it closes the circuit. When
released it springs backward and opens the circuit again.
They are principally used for ringing bells. If the latter are of the
automatic type, they ring as long as the button is pressed.
For door-bells and room-bells, the button often occupies the center of a
rosette of wood or bronze or other ornamental piece. Sometimes, as shown
in the cut, they are constructed for use on floors to be pressed by the
foot. The general principle of their construction is shown, although the
method of making the contact varies.
Synonym--Press Button.
Fig. 71. FLOOR PUSH BUTTON.
94 STANDARD ELECTRICAL DICTIONARY.
Burning.
(a) In a dynamo, the production of shifting and temporary arcs between
the commutator and brushes, which arcs produce heat enough to injure the
parts in question.
(b) In electro-plating, a defect due to too strong a current in
proportion to the strength of solution and area of electrodes. This
gives a black or badly-colored deposit.
Bus Rod.
A copper conductor used in electric lighting or power stations, to
receive the current from all the dynamos. The distributing leads are
connected to the bus wires.
In the three-wire system there are three; in the two-wire system there
are two bus wires.
The name is undoubtedly derived from "omnibus."
The bus wires may be divided into positive, negative, and, in the
three-wire system, neutral bus wires.
Synonyms--Omnibus Rod, Wire, or Bar--Bus Bar, or Wire.
Buzzer.
An electric alarm or call produced by a rapid vibration of electric make
and break mechanism, which is often magnified by enclosure in a
resonating chamber, resembling a bell, but which is not struck or
touched by the vibrating parts. Sometimes a square wooden box is used as
resonator.
Fig. 72. BUZZER.
95 STANDARD ELECTRICAL DICTIONARY.
B. W. G.
Abbreviation for Birmingham Wire Gauge. (See Wire Gauge, Birmingham.)
C.
(a) Abbreviation for Centigrade, as 100 C., meaning 100 Centigrade. (See
Centigrade Scale.)
(b) A symbol of current or of current strength. Thus in the expression
of Ohm's law C = E/R. C indicates current strength or intensity, not in
any fixed unit, but only in a unit of the same order in which E and R
are expressed; E Indicating electro-motive force and R resistance.
Cable.
(a) Abbreviation for Cablegram, q. v.
(b) v. It is also used as a verb, meaning to transmit a message by
submarine cable.
(c). An insulated electric conductor, of large diameter. It often is
protected by armor or metallic sheathing and may be designed for use as
an aerial, submarine, subterranean or conduit cable. A cable often
contains a large number of separately insulated conductors, so as to
supply a large number of circuits.
Cable, Aerial.
A cable usually containing a large number of separately insulated wires,
and itself insulated. It is suspended in the air. As its weight is
sometimes so great that it could not well sustain it, a suspending wire
is in such cases carried along with it, to which it is suspended by
cable hangers, q. v.
Cable Box.
A box for receiving underground cable ends and connecting the separate
wires of the cable to air-line wires. It is often mounted on a pole,
which forms the starting point of the air-line portion of the system.
Cable, Bunched.
A cable containing a number of separate and individual conductors. In
some forms it consists virtually of two or more small cables laid
tangent to each other and there secured. Thus each in section represents
two or more tangent circles with the interstice solidly filled with the
metal sheathing.
Cable, Capacity of.
The electrostatic capacity of a cable. A cable represents a Leyden jar
or static condenser. The outer sheathing or armor, or even the more or
less moist coating, if it is unarmored, represents one coating. The wire
conductors represent the other coating, and the insulator is the
dielectric.
The capacity of a cable interferes with its efficiency as a conductor of
broken or interrupted currents, such as are used in telegraphy or
telephoning. As each impulse or momentary current is sent into the line,
it has to charge the cable to at least a certain extent before the
effects of the current are perceptible at the other end. Then the cable
has to discharge itself. All this creates a drag or retardation.
The capacity of a cable is used to determine the locality of breaks in
the continuity of the conductors. The capacity per unit of length being
accurately known, it is obvious that, if the conductor breaks without
disturbance of the insulator, the distance of the break from the end can
be ascertained by determining the capacity of the cable from one end.
This capacity will be in proportion to the capacity of a mile, a knot or
any fixed unit, as the distance to the break is to the length used as
standard.
96 STANDARD ELECTRICAL DICTIONARY.
Cable Core.
The conductors of a cable. They are generally copper wire. In a
telephone cable they may be very numerous and insulated from each other.
In ocean cables they may be a group of bare wires twisted or laid
together. Sometimes the conductors are arranged for metallic circuits,
each pair being distinguished by special colored windings.
Cable, Duplex.
A cable containing two wires, each with separate insulation, so as to be
virtually two cables, laid and secured parallel and side by side.
Cable, Flat.
A cable, flat in shape, so as to lie closely against a wall or ceiling.
Cablegram.
A message which has been transmitted or is to be transmitted by a
submarine cable. It is sometimes called a cable.
Cable Grip.
A grip for holding the end of a cable, when the cable is to be drawn
into a conduit in a subway. It is an attachment to provide the cable
with an eye or loop. Its end is a split socket and embraces the end of
the cable, and is secured thereto by bolts driven through the cable end.
In drawing a cable into a conduit a capstan and rope are often used, and
the rope is secured to the cable end by the grip.
Fig. 73. CABLE HANGER, CABLE, AND SUSPENDING WIRE.
Fig. 74. CABLE HANGER, OPEN.
Cable Hanger.
When a heavy electric cable is suspended from poles it often would be
unsafe to trust to its longitudinal strength to support or sustain its
own weight unless the poles were very near together. In such case an
auxiliary or sustaining wire is run along with it, and by clips or
hangers the cable is connected thereto at as frequent intervals as seem
desirable. The contrivance may take the form of a strip of metal
surrounding the cable and carrying a hook or eye through which the
supporting wire passes.
Synonym--Cable Clip.
97 STANDARD ELECTRICAL DICTIONARY
Cable Hanger Tongs.
Tongs for attaching cable hangers, q.v. They have long handles so as to
be worked from the ground at the middle of a span.
Cable, Suspending Wire of.
A wire by which an aerial cable is in part or entirely suspended. The
cable, being incapable of sustaining its own weight, is secured by clips
or hangers to a wire, strong from pole to pole immediately above it.
(See Cable Hanger.)
Cable Tank.
A tank in which a submarine cable is coiled away on board a cable-laying
ship, or in the factory on shore for the purpose of testing or
watching its insulation. Sometimes, in order to test it under pressures
approximating to those it will be subjected to in practice, the tank is
closed and the portion of cable within it is subjected to hydraulic
pressure. This represents the pressure it will be exposed to in deep
water.
Calamine.
A mineral; zinc silicate; formula Zn2 Si 03, crystalline system,
Orthorhombic; specific gravity, 3.16-3.9.
The crystals often show strong pyroelectric properties.
Calibration.
The determination by experiment or calculation of the value of the
readings of an instrument, such as a galvanometer or eudiometer. Thus if
a tangent galvanometer has its circle graduated in degrees, a table of
the value of tangents corresponding to every reading occurring in
practice would represent a calibration by calculation. A determination
of the current required to produce each deflection would be a
calibration in the more usual sense. Calibration is generally absolute,
as referring to some fixed unit, but it may be relative, as between two
things both of unknown absolute value.
Calibration, Absolute.
The determination of the absolute value of currents producing given
deflections in a galvanometer, or in other instruments the determination
of corresponding values, as the instrument may be a magnetometer,
quadrant electrometer, or other apparatus.
Calibration, Invariable.
Calibration applicable to specially constructed galvanometers, which is
unaffected by the proximity of masses of iron or field magnets. Such
galvanometers must have a constant controlling field. Such is given by a
powerful permanent magnet, whose field is practically unaffected by the
causes named. Or else, in place of a controlling field, a spring maybe
used to which the needle is attached, and which tends to hold it in one
position.
98 STANDARD ELECTRICAL DICTIONARY.
Calibration, Relative.
The determination of the law connecting the various indications of an
instrument, such as the deflections of the needle of a galvanometer,
with the relative causes; in the case of a galvanometer, the strength of
the currents or the electro-motive forces producing them directly or
indirectly.
Call Bell.
A bell rung by pressing a button or otherwise to call the attention of a
person in a distant place. They can be classified into a great variety
of types according to their uses or construction.
Call Button.
A push button used for ringing a call bell, sounding a buzzer, working
an annunciator and for similar purposes. (See Push Button.)
Synonym--Push Button.
Calling Drop.
In a telephone exchange or telegraph office a drop shutter annunciator,
which falls to call the attention of the operator, notifying him that
the line connected to such drop is to be connected to some other
circuit.
Calorie or Calory.
A practical unit of heat. There are two calories, respectively called
the great and the small calorie, or the kilogram and the gram calorie.
The first is the quantity of heat required to raise the temperature of
one kilogram of water one degree centigrade. The second is the quantity
of heat required to raise the temperature of one gram of water one
degree centigrade.
Calorimeter.
An apparatus for measuring the quantity of heat evolved or produced by
or under different conditions. Dulong's water calorimeter consists of a
water jacket, and by the increase of temperature of the water and
enclosing vessels the amount of heat produced by anything in the inner
vessels is determined. The amount of ice a heated body will melt is
sometimes made the basis of a calorimeter. The expansion of a fluid, as
water, may be used. In the calorimeter shown in the cut the heat
produced in a conductor by the passage of an electric current is caused
to heat water whose temperature is shown by a thermometer immersed
therein. The increase of temperature and the weight of the water give
the basis for a determination of the heat produced by the current.
Knowing the resistance of the conductor immersed, the watts can be
calculated. This gives the bases for the determination of the
heat-equivalent of electric energy. This is but an imperfect
calorimeter, as it constantly would lose heat by the surrounding
atmosphere, and would cease to operate as a calorimeter when the water
was as hot as the wire normally would be, for then it would not absorb
all the heat.
Fig. 75. CALORIMETER.
99 STANDARD ELECTRICAL DICTIONARY.
Candle.
The generally accepted unit of illuminating power; there are
three kinds in use as standards. (See Candle, Decimal--Candle, German
Standard--Candle, Standard.)
Candle, Concentric.
An electric candle of the Jablochkoff type, having a small solid carbon
inside of an outside tubular carbon, the space between being filled with
refractory material corresponding to the colombin, q. v., of the
ordinary type. The arc springs across from one carbon to the other.
Candle, Debrun.
An arc lamp with approximately parallel carbons. A transverse priming
connects their bases, and the arc starting there at once flies out to
the end.
Candle, Decimal.
A standard of illuminating power, proposed to the Congress of
Electricians of 1889 by Picou. It is one-twentieth of a Viole, or almost
exactly one standard candle. (See Viole's Standard of Illuminating
Power.)
Candle, Electric.
An arc lamp regulated by simple gravity, or without any feed of the
carbons or special feeding apparatus, generally for the production of an
arc light of low intensity. This definition may be considered too
elastic, and the word may be restricted to parallel carbon lamps in
which the arc springs across from carbon to carbon. For the latter class
an alternating current is used to keep the carbons of equal length. They
are but little used now. Various kinds have been invented, some of which
are given here.
Candle, German Standard.
A standard of illuminating power used in Germany. It is a paraffin
candle, 6 to the pound, 20 millimeters diameter; flame, 56 millimeters
high; rate of consumption, 7.7 grams per hour. Its value is about two
per cent. lower than the English standard candle.
100 STANDARD ELECTRICAL DICTIONARY.
Candle Holder.
A clamp for holding electric candles of the Jablochkoff type. The ones
shown in the cut designed for Jablochkoff candles comprise a pair of
metallic clamps, each member insulated from the other, and connected as
terminals of the circuit. When the candle is placed in position the
metal pieces press against the carbons of the candle and thus convey the
current. Below each member of the clamps is a binding screw for the line
wire terminals.
Fig. 76. JABLOCHKOFF CANDLE HOLDERS.
Fig. 77. JABLOCHKOFF CANDLE.
Candle, Jablochkoff.
An arc lamp without regulating mechanism, producing an arc between the
ends of parallel carbons. It consists of two parallel rods of carbon,
between which is an insulating layer of non-combustible material called
the colombin. Kaolin was originally employed for this part; later, as
the fusion of this material was found to short- circuit the arc, a
mixture of two parts of calcium sulphate and one of barium sulphate was
used. The carbons are 4 millimeters (.16 inch) thick, and the colombin
is 3 millimeters (.12 inch) wide and two-thirds as thick. A little slip
of carbon is placed across the top, touching both carbons to start the
arc. Once started the candle burns to the end, and cannot be restarted
after ignition, except by placing a short conductor across the ends, as
at first. The Jablochkoff candle may now be considered as virtually
extinct in this country. In France at one time a great number were in
use.
To keep the carbons of equal length an alternating current must always
be used with them. Special alternating combinations were employed in
some cases where a direct current had to be drawn upon.
Candle, Jamin.
An arc lamp with approximately parallel carbons, one of which oscillates
and is controlled by an electro-magnet and armature. A coil of wire is
carried around the carbons to keep the arc steady and in place. The
frame and wire coils have been found unsatisfactory, as causing a
shadow.
Candle Power.
The amount of light given by the standard candle. The legal English and
standard American candle is a sperm candle burning two grains a minute.
It should have burned some ten minutes before use, and the wick should
be bent over and have a red tip. Otherwise its readings or indications
are useless. A sixteen candle power lamp means a lamp giving the light
of sixteen candles. The candle power is a universal unit of illuminating
power.
101 STANDARD ELECTRICAL DICTIONARY.
Candle Power, Rated.
The candle power of arc lamps is always stated in excess of the truth,
and this may be termed as above. A 2000 candle power lamp really gives
about 800 candles illumination.
Synonym--Nominal Candle Power.
Candle Power, Spherical.
The average candle power of a source of light in all directions. An arc
lamp and an incandescent lamp vary greatly in the intensity of light
emitted by them in different directions. The average of a number of
determinations at various angles, the lamp being moved about into
different positions, is taken for the spherical candle power.
Candle, Standard.
A standard of illuminating power. Unless otherwise expressed the English
standard sperm candle is indicated by this term. (See Candle Power.)
Candle, Wilde.
An arc lamp with approximately parallel carbons. One of the carbons can
rotate through a small arc being pivoted at its base. This oscillation
is regulated by an electro-magnet at its base, and the carbons touch
when no current is passing. They separate a little when the current
passes, establishing an arc. The regulation is comparable to that of a
regular arc lamp.
Fig. 78. WILDE CANDLE.
Caoutchouc.
India rubber; a substance existing in an emulsion or solution in the
juice of certain trees and vines of the tropics, whence it is obtained
by coagulation and drying. The name "rubber" is due to the fact that one
of its earliest uses was for erasing pencil marks by rubbing. It has a
very high value as an insulator. The unworked crude rubber is called
virgin gum; after working over by kneading, it is termed masticated or
pure gum rubber; after mixture with sulphur and heating, it is termed
vulcanized rubber. If enough sulphur is added it becomes hard, and if
black, is termed ebonite; if vermilion or other pigment is also added to
produce a reddish color, it is termed vulcanite. The masticated gum
dissolves more or less completely in naphtha (sp. gr., .850) benzole,
turpentine, chloroform, ether and other similar liquids.. The resistance
per centimeter cube of "Hooper's" vulcanized India rubber, such as is
used in submarine cables is 1.5E16 ohms. The specific inductive capacity
of pure India rubber is 2.34--of vulcanized 2.94 (Schiller).
Synonyms--India Rubber--Rubber.
102 STANDARD ELECTRICAL DICTIONARY.
Capacity, Dielectric.
The capacity of a dielectric in retaining an electrostatic charge; the
same as Specific Inductive Capacity. 'The number expressing it is
sometimes called the dielectric constant. (See Capacity, Specific
Inductive.)
Capacity, Electric, or Electrostatic.
The relative capacity of a conductor or system to retain a charge of
electricity with the production of a given difference of potential. The
greater the charge for a given change of potential, or the less the
change of potential for a given charge the greater the capacity. The
measure of its capacity is the amount of electricity required to raise
the potential to a stated amount. The unit of capacity is the farad, q.
v. Electric capacity is comparable to the capacity of a bottle for air.
A given amount of air will raise the pressure more or less, and the
amount required to raise its pressure a stated amount might be taken as
the measure of capacity, and would be strictly comparable to
electrostatic charge and potential change. The capacity, K, is obviously
proportional to the quantity, Q, of the charge at a given potential, E,
and inversely proportional to the potential, E, for a given quantity, Q,
or,
(1) K == Q/E
and
(2) Q = K * E,
or, the quantity required to raise a conductor by a given potential is
equal to the capacity of the conductor or system multiplied by the rise
of potential. The capacity of a conductor depends upon its environments,
such as the nature of the dielectric surrounding it, the proximity of
oppositely charged bodies and other similar factors. (See
Dielectric-Condenser-Leyden jar.)
The dimensions of capacity are found by dividing a quantity of
electricity by the potential produced in the conductor by such
quantity.
Quantity ( ((M^.5)*(L^1.5)) / T ) / potential ( ((M^.5)*(L^.5)) / T ) = L.
Capacity, Instantaneous.
The capacity of a condenser when connected only for an instant to a
source of electricity. This is in contrast to electric absorption (see
Absorption, Electric), and is capacity without such absorption taking
part in the action.
103 STANDARD ELECTRICAL DICTIONARY.
Capacity of a Telegraph Conductor.
The electric capacity of a telegraphic conductor is identical in quality
with that of any other conductor. It varies in quantity, not only for
different wires, but for the same wire under different environments, as
the wire reacting through the surrounding air or other dielectric upon
the earth, represents one element of a condenser, the earth, in general,
representing the other. Hence, a wire placed near the earth has greater
capacity than one strung upon high poles, although the wires may be
identical in length, material and diameter. The effect of high capacity
is to retard the transmission of intermitting signals. Thus, when--as in
the Morse system--a key is depressed, closing a long telegraph current
and sending a signal into a line, it is at least very probable that a
portion of the electricity travels to the end of the wire with the
velocity of light. But as the wire has to be charged, enough current to
move the relay may not reach the end for some seconds.
Capacity of Polarization of a Voltaic Cell.
The relative resistance to polarization of a voltaic cell, measured by
the quantity of electricity it can supply before polarization. A
counter-electromotive force may be developed, or the acid or other
solution may become exhausted. The quantity of electricity delivered
before this happens depends on the size and type of cell and other
factors.
Capacity, Residual.
When two insulated conductors are separated by a dielectric, and are
discharged disruptively by being connected or nearly connected
electrically, on removing the discharger it is found that a slight
charge is present after a short interval. This is the residual charge.
(See Charge, Residual.) Shaking or jarring the dielectric facilitates
the complete discharge. This retaining of a charge is a phenomenon of
the dielectric, and as such, is termed residual capacity. It varies
greatly in different substances. In quartz it is one-ninth what it is in
air. Iceland spar (crystalline calcite) seems to have no residual
capacity. The action of shaking and jarring in facilitating a discharge
indicates a mechanical stress into which the electrostatic polarization
of the conductor has thrown the intervening dielectric.
Capacity, Specific Inductive.
The ratio of the capacity of a condenser when its plates are separated
by any substance to the capacity of the same condenser when its plates
are separated by air.
A static accumulator consists of two conducting surfaces separated by an
insulator. It is found that the capacity of an accumulator for an
electric charge, which varies with or may be rated by the potential
difference to which its conductors will be brought by the given charge,
varies with the nature of the interposed dielectric, and is proportional
to a constant special to each substance. This constant is the specific
inductive capacity of the dielectric.
The same condenser will have a higher capacity as the dielectric is
thinner, other things being equal. But different dielectrics having
different specific inductive capacities, the constant may be determi
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