Electrical Apparatus for diminishing the apparent Self-Induction of Alternating Current Circuits, and capable of being used in lieu of Condensers.
Year: 1899

page_text: Date of Application, 11th Apr., 1899
Complete Specification Left, 21st Dec., 1899-Accepted, 17th Feb., 1900
PROVISIONAL SPECIFICATION.
Electrical Apparatus for diminishing the apparent Self-Induction
of Alternating Current Circuits, and capable of being used in
lieu of Condensers.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Buildings,
in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by La Société Anonyme pour la Transmission de la Force par L'electricité, of
13, Rue Lafayette, Paris, France, Manufacturers,) to be as follows:-
This invention has reference to a new construction of electrical apparatus serving
the same purpose as condensers and capable, like these, of diminishing the apparent
coefficient of self induction of a circuit through which alternating currents are
passed.
The apparatus consists of a moveable galvanometer frame through the coil of
which passes the alternating current to be acted upon. This frame can oscillate
freely in a uniform magnetic field. If such an apparatus is suitably proportioned it
will develop in any circuit in which the frame coil is included the same electromotive
forces as a condenser.
Thus assuming a construction in which a horse shoe magnet produces a magnetic
field of the intensity J, and in which is suspended a galvanometer frame the moment
of inertia of which is = u through the coil of which frame passes an alternating
current i a Sin 2 wt; the resistance of the moveable frame is assumed to be ?",
and its coefficient of self induction = 1.
When the angle formed by the plane of the galvanometer frame with the plane
passing through the poles of the magnet has the value 6, the elastic reaction of the
suspension threads will be = K 0.
The deadening force due to the density of the surrounding air may be represented
do
by 9
The frame will be subjected at each moment to the effects of a motor couple M
proportional to the intensity of the field J, and to the intensity of the current i.
Designating by A a constant depending upon the mode of construction of the

page_text: If B represent a constant dependent on the mode of construction of the apparatus,
then,
The coefficient of self induction of the frane will therefore be increased or
diminished according as the second term of the equation of A is positive or
negative.
By a special construction the elastic reaction of the supports of the frame can
always be rendered nought, for instance by employing pivots instead of suspension
threads.
1.1.
]
As in general the deadening forces will be small relatively to the force of inertia,
the term 92 can be neglected, and we then have:
It suffices to render the quantity A negative, in order to enable the arrangement
described to perform the office of a condenser; this would be the easier, the lighter
the frame were made, the more powerful were the field in which it oscillates, and
the lower were the frequency of the currents passing through the frame.
The action of the apparatus can be regulated at will by varying the intensity J
of the inducing field.
In the same way as a condenser can be combined in series or in parallel with the
circuit of which the self induction is to be diminished, the above described apparatus
can also be combined either in series or in parallel with that circuit.
According to one arrangement for carrying out the above described invention, two
annular pieces of steel are fitted together in such manner that a cross section thereof
has the form of a double horse shoe magnet having a narrow space between the
limbs, part of which space enlarged to receive a circular magnetising coil so that
on the passage of a continuous current through the coils a magnetic field is produced

page_text: in the narrow spaces between the limbs of the steel pieces. In these horizontally
arranged spaces is arranged a copper disc fixed on a central vertical axis with which
it can rotate, the periphery of the disc being bent downwards at a slight angle.
1
The surface of the narrow space of the steel pieces situated above the copper disc
is covered with an insulated copper disc. In the lower surface of the said narrow
space is formed an insulated circular channel filled with mercury into which the
peripheries of both copper discs dip, so that they are in electrical communication.
with each other.
An electric current being passed in through the axis of the moveable copper disc,
it will pass first through this disc and then into the fixed disc which will conduct
it back to the centre where it is taken off by a sliding contact.
Instead of mercury any other suitable device may be employed for effecting the
connection between the moveable and fixed discs.
The same results may be obtained by means of any continuous current dynamo
the induced part of which can oscillate freely on its axis when left to itself.
It would be advisable in this case to construct the induced part without an iron
core so that the momentum of inertia may be as small as possible.
This apparatus which may be termed an electrical recuperator is mainly applicable.
with asynchronous alternating current machines whether employed as generators or.
motors.
If the above described apparatus be included in the induced circuits of such
machines through which are normally passed currents of very low frequency, the
apparent self induction of these circuits can be thereby reduced to any desired
degree.
By this means it is possible, firstly to give these machines a considerable inter
polar air space, without affecting their power, as the effect of the magnetic leakages
is destroyed; secondly, if these machines are employed as generators they can be
arranged to supply dewatted currents as well as watted currents; thirdly, if these
machines are employed as receivers they can have a cosine o imparted to them as
near as possible to unity or even negative.
Dated this 11th day of April 1899.
ABEL & IMRAY,
Agents for the Applicant.
Electrical Apparatus for diminishing the apparent Self-Induction
of Alternating Current Circuits, and capable of being used in
lieu of Condensers.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Buildings,
in the County of London, Consulting Engineer and Chartered Patent Agent, do
hereby declare the nature of this invention (as communicated to me from abroad
by La Société Anonyme pour la Transmission de la Force par L'electricité, of 13, Rue.
Lafayette, Paris, France, Manufacturers,) and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
This invention has reference to a new construction of electrical apparatus serving.
the same purpose as condensers and capable, like these, of diminishing the apparent
coefficient of self induction of a circuit through which alternating currents are
passed.
The apparatus consists of a movable galvanometer frame through the coil of which
passes the alternating current to be acted upon. This frame can oscillate freely in a

page_text: The voltage E which will be developed between the extremities of the frame will
depend upon its resistance, its coefficient of self induction, and its displacement in
the field.
If B represent a constant dependent on the mode of construction of the apparatus, 2

page_text: diminished according as the second term of the equation of A is positive or
negative.
By a special construction the elastic reaction of the supports of the frame can
always be rendered nil, for instance by employing pivots instead of suspension
threads.
In that case we should have.
It suffices to render the quantity & negative, in order to enable the arrangement
described to perform the office of a condenser; this would be the easier, the lighter
the frame were made, the more powerful were the field in which it oscillated, and the
lower were the frequency of the currents passing through the frame.
The action of the apparatus can be regulated at will by varying the intensity J of
the inducing field.
In the same way as a condenser can be combined in series or in parallel with the
circuit of which the self induction is to be diminished, the above described apparatus
can also be combined either in series or in parallel with that circuit.
According to one arrangement for carrying out the above described invention,
shewn in Fig. 2 of the accompanying drawings, two annular pieces of steel A B are
fitted together in such manner that a cross section thereof presents an annular
hollow C D E F occupied by a circular magnetising coil M, so that on the passage of
a continuous current through the coils a magnetic field is produced in the narrow
spaces between the limbs of the steel pieces A B. In these spaces there is mounted
a copper disc [{ b fixed on a central vertical axis X Y with which it can rotate, the
periphery of the disc being bent downwards at a slight angle.
The under surface of A in the narrow space between the steel pieces above the
copper disc abis covered with an insulated copper disc c d. In the upper surface
of B in the narrow space is formed an insulated annular channel filled with mercury
into which the peripheries of both copper discs dip, so that they are in electrical
communication with each other.
An electric current being passed by a rubbing contact into the axis a y, it will pass
first through this disc a band then into the fixed dise c d which will conduct it back
to the centre where it is taken off by a contact at S. When the current is continuous
the disc ab rotates in one direction.
Instead of mercury, rubbers may be employed for effecting the connection between
the moveable and the fixed disc.
The same results may be obtained by means of any continuous current dynamo the
induced part of which can oscillate freely on its axis when left to itself.
It would be advisable in this case to construct the induced part without au iron
core so that the moment of inertia may be as small as possible.
This apparatus which may be termned an electrical recuperator, is mainly applicable
with asynchronous alternating current machines whether employed as generator
or motors.
If the above described apparatus be included in the induced circuits of such
machines through which are norinally passed currents of very low frequency, the
apparent self induction of these circuits can be thereby reduced to any desired
degree.
By this means it is possible, firstly to give these machines a considerable inter
polar air space, without affecting their power, as the effect of the magnetic leakages

page_text: is destroyed; secondly, if these machines are employed as generators they can bé
arranged to supply dewatted currents as well as watted currents; thirdly, if these
machines are employed as receivers they can have a cosine imparted to them as
near as possible to unity or even negative.
Having thus particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
clain is-
1. Apparatus for diminishing the apparent self induction of an alternating current
circuit and capable of operating as a condenser, comprising a constant polar field in
which can freely oscillate a conductor connected to the alternating current circuit,
substantially as described.
2. Apparatus for the purpose above set forth constructed and operating substan-
tially as described with reference to Fig. 2.
Dad 014
CD
1000
ABEL & IMRAY,
Agents for the Applicant.