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

by T. O'Conor Sloane

Fig. 280. PYROMAGNETIC GENERATOR.
Pyrometer, Siemens' Electric.
An instrument for measuring high temperatures by the variations in
electric resistance in a platinum wire exposed to the heat which is to
be measured.

443 STANDARD ELECTRICAL DICTIONARY.
Q.
Symbol for electric quantity.
Quad.
(a) A contraction for quadrant, used as the unit of inductance; the henry.
(b) A contraction for quadruplex in telegraphy.
[Transcriber's note: A modern use of "quad" is a unit of energy equal to
1E15 (one quadrillion) BTU, or 1.055E18 joules. Global energy
production in 2004 was 446 quad.]
Quadrant.
A length equal to an approximate earth quadrant, equal to 1E9
centimeters. It has been used as the name for the unit of inductance,
the henry, q. v.
Synonym--Standard Quadrant.
444 STANDARD ELECTRICAL DICTIONARY.
Quadrant, Legal.
The accepted length of the quadrant of the earth, 9.978E8 instead of 1E9
centimeters; or to 9,978 kilometers instead of 10,000 kilometers.
Quadrature.
Waves or periodic motions the angle of lag of one of which, with
reference to one in advance of it, is 90°, are said to be in quadrature
with each other.
[Transcriber's note: If the voltage and current of a power line are in
quadrature, the power factor is zero (cos(90°) = 0) and no real power
is delivered to the load.]
Qualitative.
Involving the determination only of the presence or absence of a
substance or condition, without regard to quantity. Thus a compass held
near a wire might determine qualitatively whether a current was passing
through the wire, but would not be sufficient to determine its quantity.
(See Quantitative.)
Quality of Sound.
The distinguishing characteristic of a sound other than its pitch; the
timbre.
It is due to the presence with the main or fundamental sound of other
minor sounds called overtones, the fundamental note prevailing and the
other ones being superimposed upon it. The human voice is very rich in
overtones; the telephone reproduces these, thus giving the personal
peculiarities of every voice.
Synonym--Timbre.
Quantitative.
Involving the determination of quantities. Thus a simple test would
indicate that a current was passing through a wire. This would be a
qualitative test. If by proper apparatus the exact intensity of the
current was determined, it would be a quantitative determination. (See
Qualitative.)
Quantity.
This term is used to express arrangements of electrical connections for
giving the largest quantity of current, as a quantity armature, meaning
one wound for low resistance.
A battery is connected in quantity when the cells are all in parallel.
It is the arrangement giving the largest current through a very small
external resistance.
The term is now virtually obsolete (Daniell); "in surface," "in
parallel," or "in multiple arc" is used.
Quantity, Electric.
Electricity may be measured as if it were a compressible gas, by
determining the potential it produces when stored in a defined
recipient. In this way the conception of a species of quantity is
reached. It is also measured as the quantity of current passed by a
conductor.
Thus a body whose surface is more or less highly charged with
electricity, is said to hold a greater or less quantity of electricity.
It may be defined in electrostatic or electro-magnetic terms. (See
Quantity, Electrostatic--Quantity, Electro-magnetic.)
445 STANDARD ELECTRICAL DICTIONARY.
Quantity.
Electro-magnetic. Quantity is determined electro-magnetically by the
measurement of current intensity for a second of time: its dimensions
are therefore given by multiplying intensity or current strength by
time. The dimensions of intensity are
( (M^.5) * (L^.5) ) / T
therefore the dimensions of electro-magnetic quantity are
( ( (M^.5) * (L^.5) ) / T ) * T = ( (M^.5) * (L^.5) )
Quantity, Electro-magnetic, Practical Unit of.
The quantity of electricity passed by a unit current in unit time; the
quantity passed by one ampere in one second; the coulomb.
It is equal to 3E9 electrostatic absolute units of quantity and to 0.1
of the electro- magnetic absolute unit of quantity.
One coulomb is represented by the deposit of
.00111815 gram, or .017253 grain of silver,
.00032959 gram, or .005804 grain of copper,
.0003392 gram, or .005232 grain of zinc.
If water is decomposed by a current each coulomb is represented by the
cubic centimeters of the mixed gases (hydrogen and oxygen) given by the
following formula.
( 0.1738 * 76 * (273 + Cº ) ) / ( h * 273 )
in which Cº is the temperature of the mixed gases in degree centigrade
and h is the
pressure in centimeters of mercury column; or by
( 0.01058 * 30 (491 + Fº - 32) ) / (h * 491 )
for degrees Fahrenheit and inches of barometer.
[Transcriber's note: 6.24150962915265E18 electrons is one coulomb.]
Quantity, Electrostatic.
Quantity is determined electro-statically by the repulsion a charge of
given quantity exercises upon an identical charge at a known distance.
The force evidently varies with the product of the two quantities, and
by the law of radiant forces also inversely with the square of the
distance. The dimensions given by these considerations is Q * Q/(L*L).
This is the force of repulsion. The dimensions of a force are
(M * L) /(T^2). Equating these two expressions we have:
(Q^2)/(L^2) = (M*L)/(T^2)
or
Q = ((M^.5)*(L^1.5)) / T
which are the dimensions of electrostatic quantity.
Quantity, Meter.
An electric meter for determining the quantity of electricity which
passes through it, expressible in coulombs or ampere hours. All
commercial meters are quantity meters.
446 STANDARD ELECTRICAL DICTIONARY.
Quartz.
A mineral, silica, SiO2. It has recently been used by C. V. Boys and
since by others in the making of filaments for torsion suspensions. The
mineral is melted, while attached to an arrow or other projectile. It is
touched to another piece of quartz or some substance to which it adheres
and the arrow is fired off from the bow. A very fine filament of
surpassingly good qualities for galvanometer suspension filaments is
produced.
As a dielectric it is remarkable in possessing but one-ninth the
residual capacity of glass.
Quicking.
The amalgamating of a surface of a metallic object before silver
plating. It secures better adhesion of the deposit. It is executed by
dipping the article into a solution of a salt of mercury. A solution of
mercuric nitrate 1 part, in water 100 parts, both by weight, is used.

446 STANDARD ELECTRICAL DICTIONARY.
R.
(a) Abbreviation and symbol for Reamur, as 10º R., meaning 10º by the
Reamur thermometer. (See Reamur Scale.)
(b) Symbol for resistance, as in the expression of Ohm's Law C=E/R.
(rho, Greek r) Symbol for specific resistance.
Racing of Motors.
The rapid acceleration of speed of a motor when the load upon it is
removed. It is quickly checked by counter-electro-motive force. (See
Motor, Electric.)
Radian.
The angle whose arc is equal in length to the radius; the unit angle.
Radiant Energy.
Energy, generally existing in the luminiferous ether, kinetic and
exercised in wave transmission, and rendered sensible by conversion of
its energy into some other form of energy, such as thermal energy.
If the ether waves are sufficiently short and not too short, they
directly affect the optic nerve and are known as light waves; they may
be so short as to be inappreciable by the eye, yet possess the power of
determining chemical change, when they are known as actinic waves; they
may be also so long as to be inappreciable by the eye, when they may be
heat-producing waves, or obscure waves.
Other forms of energy may be radiant, as sound energy dispersed by the
air, and gravitational energy, whose connection with the ether has not
yet been demonstrated.
Radiation.
The traveling or motion of ether waves through space.
[Transcriber's note: The modern term corresponding to this definition is
photons. The modern concept of radiation also includes particles--
neutrons, protons, alpha (helium) and beta (electrons) rays and other
exotic items.]
Radicals.
A portion of a molecule, possessing a free bond and hence free to
combine directly. A radical never can exist alone, but is only
hypothetical. An atom is a simple radical, an unsaturated group of atoms
is a compound radical.
447 STANDARD ELECTRICAL DICTIONARY.
Radiometer.
An instrument consisting of four vanes poised on an axis so as to be
free to rotate, and contained in a sealed glass vessel almost perfectly
exhausted. The vanes of mica are blackened on one side.
On exposure to light or a source of heat (ether waves) the vanes rotate.
The rotation is due to the beating back and forth of air molecules from
the surface of the vanes to the inner surface of the glass globe.
Radiometer, Electric.
A radiometer in which the motion of the molecules of air necessary for
rotation of the vane is produced by electrification and not by heating.
Radio-micrometer.
An instrument for detecting radiant energy of heat or light form. It
consists of a minute thermopile with its terminals connected by a wire,
the whole suspended between the poles of a magnet. A minute quantity of
heat produces a current in the thermopile circuit, which, reacted on by
the field, produces a deflection. A convex mirror reflecting light is
attached so as to move with the thermopile. The instrument is of
extraordinary sensitiveness. It responds to .5E-6 of a degree Centigrade
or about 1E-6 degree Fahrenheit.
Radiophony.
The production of sound by intermittent action of a beam of light upon a
body. With possibly a few exceptions all matter may produce sound by
radiophouy.
Range Finder.
An apparatus for use on shipboard to determine the distance of another
ship or object. It is designed for ships of war, to give the range of
fire, so as to set the guns at the proper elevation. The general
principle involved is the use of the length of the ship if possible, if
not of its width, as a base line. Two telescopes are trained upon the
object and kept trained continuously thereon. The following describes
the Fiske range finder.
The range finder comprises two fairly powerful telescopes, each mounted
on a standard, which can be rotated round a vertical axis, corresponding
with the center of the large disc shown in the engraving. One-half of
the edge of this disc is graduated to 900 on either side of a zero
point, and below the graduation is fixed a length of platinum silver
wire. This wire only extends to a distance of 81.10 on either side of
zero, and is intended to form two arms of a Wheatstone bridge. The
sliding contact is carried by the same arm as the telescope standards,
so that it moves with the telescope. The two instruments are mounted at
a known distance apart on the ship, as shown diagrammatically in the
cut. Here A and B are the centers of the two discs, C and D the arms
carrying the telescopes, and E and F the platinum silver wires. Suppose
the object is at T, such that A B T is a right angle, then
AT=AB/sin(ATB).
448 STANDARD ELECTRICAL DICTIONARY.
If the two sectors are coupled up as shown, with a battery, h, and a
galvanometer, by the wires, a b and c d, then since the arm, e, on being
aligned on the object takes the position c1 while d remains at zero, the
Wheatstone bridge formed by these segments and their connections will be
out of balance, and a current will flow through the galvanometer, which
may be so graduated as to give the range by direct reading, since the
current through it will increase with the angle A T B.

Fig. 281. RANGE FINDER.
In general, however, the angle A B T will not be a right angle, but some
other angle. In this case AT = AB / sin(A T B) * sin( A B T), and hence
it will only be necessary to multiply the range reading on the
galvanometer by the sine of the angle A B T, which can be read directly
by the observer at B. This multiplication is not difficult, but by
suitably arranging his electrical appliances Lieutenant Fiske has
succeeded in getting rid of it, so that the reading of the galvanometer
always gives the range by direct reading, no matter what the angle at B
may be. To explain this, consider the two telescopes shown in the cut in
the positions C and D; the whole current then has a certain resistance.
449 STANDARD ELECTRICAL DICTIONARY.
Next suppose them, still remaining parallel, in the positions C1 and D1.
The total resistance of the circuit is now less than before, and hence
if C1, one of the telescopes, is moved out of parallel to the other,
through a certain angle, the current through the galvanometer will be
greater than if it were moved through an equal angle out of a parallel
when the telescopes were in the positions C and D. The range indicated
is, therefore, decreased, and by properly proportioning the various
parts it is found that the range can always be read direct from the
galvanometer, or in other words the multiplication of A B/sin( A T B )
by sin( A B T ) is to all intents and purposes performed automatically.
There is, it is true, a slight theoretical error; but by using a small
storage battery and making the contents carefully it is said to be
inappreciable. Each telescope is fitted with a telephone receiver and
transmitter, so that both observers can without difficulty decide on
what point to align their telescopes. It will be seen that it is
necessary that the lines of sight of two telescopes should be parallel
when the galvanometer indicates no current. It has been proposed to
accomplish this by sighting both telescopes on a star near the horizon,
which being practically an infinite distance away insures the
parallelism of the lines of sight.
Rate Governor.
An apparatus for securing a fixed rate of vibration of a vibrating reed.
It is applied in simultaneous telegraphy and telephoning over one wire.
The principle is that of the regular make and break mechanism, with the
feature that the contact is maintained during exactly one-half of the
swing of the reed. The contact exists during the farthest half of the
swing of the reed away from the attracting pole.

Fig. 282. LANGDON DAVIRS' RATE GOVERNOR.
In the left hand figure of the cut, K is the key for closing the
circuit. A is the base for attachment of the reed. V is the
contact-spring limited in its play to the right by the screw S. C is the
actuating magnet. By tracing the movements of the reed, shown on an
exaggerated scale in the three right hand figures, it will be seen that
the reed is in electric contact with the spring during about one-half
its movement. The time of this connection is adjustable by the screw S.
Synonym--Langdon Davies' Rate Governor or Phonophone.
450 STANDARD ELECTRICAL DICTIONARY.
Ray, Electric. Raia torpedo.
The torpedo, a fish having the same power of giving electric shocks as
that possessed by the electric eel, q. v. (See also Animal Electricity.)

Fig. 283. TORPEDO OR ELECTRIC RAY
Reaction of Dynamo, Field and Armature.
A principle of the dynamo current generator, discovered by Soren Hjorth
of Denmark.
When the armature is first rotated it moves in a field due to the
residual magnetism of the field magnet core. This field is very weak,
and a slight current only is produced. This passing in part or in whole
through the field magnet cores slightly strengthens the field, whose
increased strength reacts on the armature increasing its current, which
again strengthens the field. In this way the current very soon reaches
its full strength as due to its speed of rotation.
The operation is sometimes termed building up.
Sometimes, when there is but a trace of residual magnetism, it is very
hard to start a dynamo.
Reading Telescope.
A telescope for reading the deflections of a reflecting galvanometer.
A long horizontal scale is mounted at a distance from the galvanometer
and directly below or above the centre of the scale a telescope is
mounted. The telescope is so directed that the mirror of the
galvanometer is in its field of view, and the relative positions of
mirror, scale and telescope are such that the image of the scale in the
galvanometer mirror is seen by the observer looking through the
telescope.
Under these conditions it is obvious that the graduation of the scale
reflected by the mirror corresponds to the deflection of the
galvanometer needle.
The scale may be straight or curved, with the galvanometer in the latter
case, at its centre of curvature.
Reamur Scale.
A thermometer scale in use in some countries of Continental Europe. The
temperature of melting ice is 0°; the temperature of condensing steam
is 80°; the degrees are all equal in length. For conversion to
centigrade degrees multiply degrees Reamur by 5/4. For conversion to
Fahrenheit degrees multiply by 9/4 and add 32 if above 0° R., and if
below subtract 32. Its symbol is R., as 10° R.
451 STANDARD ELECTRICAL DICTIONARY.
Recalescence.
A phenomenon occurring during the cooling of a mass of steel, when it
suddenly emits heat and grows more luminous for an instant. It is a
phase of latent heat, and marks apparently the transition from a
non-magnetizable to a magnetiz able condition.
Receiver.
In telephony and telegraphy, an instrument for receiving a message as
distinguished from one used for sending or transmitting one.
Thus the Bell telephone applied to the ear is a receiver, while the
microphone which is spoken into or against is the transmitter.
Receiver, Harmonic.
A receiver including an electro-magnet whose armature is an elastic
steel reed, vibrating to a particular note. Such a reed responds to a
series of impulses succeeding each other with the exact frequency of its
own natural vibrations, and does not respond to any other rapid series
of impulses. (See Telegraph Harmonic.)
Reciprocal.
The reciprocal of a number is the quotient obtained by dividing one by
the number. Thus the reciprocal of 8 is 1/8.
Applied to fractions the above operation is carried out by simply
inverting the fraction. Thus the reciprocal of 3/4 is 4/3 or 1-1/3.
Record, Telephone.
Attempts have been made to produce a record from the vibrations of a
telephone disc, which could be interpreted by phonograph or otherwise.