An Improved Method of and Apparatus for Distributing Alternating Electric Currents.
Year: 1892

page_text: Date of Application, 5th Aug., 1892-Accepted, 10th Sept., 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by WILLIAM STANLEY, Jr., and JOHN FORREST
KELLY, both of Pittsfield, in the County of Berkshire and State of Massa-
chusetts, United States of America, Electricians.]
An Improved Method of and Apparatus for Distributing Alternating
Electric Currents.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings in the County of Middlesex, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
This invention relates to systems of electrical distribution, particularly for the
transmission of power, in which alternating currents are employed and in which the
translating devices possess more or less self induction.
When an alternating current is passed through a circuit containing such devices
the variations in the current, lag behind those of the impressed electro-motive
force through an angle which for a given periodicity of current is dependent upon
the ratio of the co-efficient of self-induction to the resistance and forces acting
in the direction of the resistance. It is well known that any considerable amount
of self induction in a circuit requires an increased capacity of the generating plant
and lowers the efficiency and economy of the system.
I have found that a condenser or a polarization cell in a shunt to the devices in
a circuit which possesses self induction will neutralize the effects of such self
induction and add very much to the efficiency of the system, as a whole.
But our
present improvement consists in locating such condensers or polarization cells at
the points of utilization of the current.
The operation of such a disposition we explain in the following manner:
The lagging or retarded current may be regarded as made up of two components,
one coinciding in phase with the impressed electro-motive force, the other at right
angles thereto. The current which flows through a condenser or polarization
cell has a negative lag with respect to the impressed electro-motive force, that is to
say the electro-motive force of the condenser or polarization cell is ahead of the
current, while the opposite is true of the electro-motive force of self-induction,
which is behind the current. If the resistance in series with the condenser or the
polarization cell be very low, the change of phase will be approximately ninety
degrees.
If, therefore, I place in shunt around the translating device a condenser or a
polarization cell of very low resistance and of such capacity that the current driven
through it by the impressed electro-motive force shall be equal in magnitude to the
lagging component of the translating device current, the two being 180° apart, will
completely neutralize each other with reference to the line and generator, and the
output demanded from the first and the loss in the second will be reduced to
proportionality to the work to be performed.
If the condenser or condensers are merely placed in parallel with the generator
and translating devices but remote from the latter, they would relieve the generator
alone, and leave the line and transformers, when such are employed, loaded down
with the lagging component and it is apparent from the above considerations that
the closer the condenser is placed to the translating device the better will be the
result secured, as the line will have to carry no false current down to that point.
This feature is particularly important in the case where transformers are used as
their size, by placing the coudensers or polarization cells on the side of the secondary
may be very materially reduced.

page_text: The accompanying drawing illustrates the invention diagrammatically.
G is a generator of alternating currents, and A, A, are the line wires of a circuit
leading from the same: B, B are transformers connected in parallel with the
circuit.
In the secondaries of these transformers alternating current motors are shown.
These are translating devices that possess self-induction.
In parallel with each motor M. and in the immediate vicinity, thereof. is a
condenser or polarization cell C, that neutralizes the self induction.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what I claim is :-
In a system of electrical generation and distribution, the combination of an
alternating current generator a conductor running therefrom for the distribution,
of the current, translating devices possessing self induction supplied with current
from the line, and condensers or polarization cells located at the points of
translation or utilization of the current and in shunt to the translating devices, as
set forth.
Dated thin 5th 1.. L
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.