The Standard Electrical Dictionary / A Popular Dictionary of Words and Terms Used in the Practice of Electrical Engineering

by T. O'Conor Sloane

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.