Improvements in Apparatus for use with Variable Currents, and in the Means of Obtaining Motive Power from Alternating Currents of Electricity.
Year: 1889

page_text: Date of Application, 25th Apr., 1889
Complete Specification Left, 27th Jan., 1890-Accepted, 25th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for use with Variable Currents, and in
the Means of Obtaining Motive Power from Alternating Currents
of Electricity.
LLEWELYN BIRCHALL ATKINSON, % W. T. Goolden & Co. Woodfield Road
Harrow Road London W.Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
The provisional specification of No. 16852 Nov. 20th 1888 relates to improve-
ments in apparatus applicable to alternate current motors, consisting in the
application of transformers with a magnetic circuit or circuits moveable in relation to the
electric circuit or circuits, whereby the function of brushes for distributing the electric
current is dispensed with by a proper variation in the position of the magnetic
circuit. The present invention is partly an extension of this principle of moveable
magnetic circuits for distributing the current, applied to self induction coils some-
times called choking coils, instead of transformer or mutual induction coils.
Suppose there are any number of circuits, connected in parallel to a source of
variable or alternating E.M.F. In each of these circuits let there be a choking
coil, the magnetic circuit of which may be closed or opened at will.
In every
circuit that has the magnetic circuit of the choking coil closed the current will be
small compared to the circuits in which the magnetic circuit of the choking coil is
open. This principle may be adapted to the constrction of apparatus for the
distribution of electric currents through various circuits and of alternating current
motors. The motor will consist of two parts, the motor part and the distributor
part. The motor contains an armature and a fixed magnetic circuit external to the
armature. The armature is wound so that for every position of a coil there are
two coils connected in parallel to a source of alternating E.M.F., but wound in
opposite directions. Under these circumstances the rotative efforts are balanced.
Each of these coils are connected with a self-inductance coil having an iron circuit,
not however closed, and revolving with the armature. During a period of half of
each revolution each of the coils are alternately covered by what may be termed a
pole piece, which short-circuits the magnetic cover. The result of this is that half
the coils on the armature of the motor have little current through them. and hence
there is a resultant rotative effort.
In the actual construction of the motor various types may be adapted. Either all
or part of the total current used may pass through coils wound on the magnets of
the motor, or the magnetization may be produced by the action of the coils on the
armature by giving the neutral line of the armature a lead in advance of the medial
magnetic plane. The whole magnetic circuit is laminated and the type of armature
is preferably that with Paccinotti projections in order to keep the magnetic resistance
as low as possible.
Dated th 4th : 1000

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for use with Variable Currents, and in
the Means of Obtaining Motive Power from Alternating Currents
of Electricity.
I, LLEWELYN BIRCHALL ATKINSON, % W. T. Goolden & Co. Woodfield Road,
Harrow Road, London, W. Civil Engineer do bereby 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 :-
The provisional specification of No. 16852 Nov. 20th 1888, relates to improve-
ments in apparatus applicable to alternate current motors, consisting in the application
of transformers with a magnetic circuit or circuits moveable in relation to the
electric circuit or circuits, whereby the function of brushes for distributing the
electric current is replaced by a proper variation in the position of the magnetic
circuit. The present invention is partly an extension of this principle of moveable
magnetic circuits for distributing the current applied to self induction coils some-
times called "choking or impedence coils," instead of "transformer or mutual
induction coils."
Suppose there are any number of circuits connected in parallel to a source of
variable or alternating E.M.F.-In each of these circuits let there be a choking
coil the magnetic circuit of which may be closed or opened at will. In every circuit
that has the magnetic circuit of the choking coil closed, the current will be small
compared to the circuit in which the magnetic circuit of the choking coil is open.
This principle may be adapted to the construction of apparatus for the distribution of
electric currents through various circuits and of alternating current motors. The
motor will consist of two parts, the motor part and the distributor part. The motor
contains an armature and a fixed magnetic circuit external to the armature. The
armature is wound so that for every usual position of a motor coil to produce rotation,
there are two coils connected in parallel to a source of alternating E.M.F. but
wound in opposite directions. Under these circumstances the rotative efforts are
balanced. Each of these coils is connected with a self inductance or impedence coil
having an internal iron circuit or coil not however closed externally and revolving
with the armature. During a period of half of each revolution each of the paired
impedence coils is alternately covered by what may be termed a pole piece which
short circuits the magnetic core. The result of this is that half the paired coils on
the motor armature have little current through them and the remainder of the motor
coils being a considerable current through them, there is a resultant rotative effort.
In the actual construction of the motor various types may be adapted. Either all,
or part of the total current used, may pass through coils wound on the field magnets
of the motor or the magnetization of the field may be induced by the action of the
coils on the armature core by giving the neutral line of the armature a lead in
advance of the medial magnetic plane. The whole magnetic circuit is laminated and
the type of armature is preferably that with Paccinotti projections, in order to keep
the magnetic resistance as low as possible. And in order that my invention may be the
better understood, I now proceed to describe the same in relation to the drawings
hereunto annexed reference being had to the letters and figures marked thereon.
Figures 1 and 2 show in diagram the essential parts and circuits of a motor con-
structed according to this invention Figure, 1. being the motor proper, Figure 2. the
distributor.
In Figure 1. A. is the laminated field magnet on which the field magnet coils are
wound. C. is the laminated armature wound with duplicate coils shown in the figure
side by side but actually superposed on one another.
In Figure 2. B. is the magnetic circuit closer consisting of half a hollow cylinder
constructed of laminated plates. D. is the rotating distributor built of laminated
plates with projections or teeth on which the coils are wound, the windings and
connections being such that the two coils on any one tooth are connected in the

page_text: same direction and the coils on alternate teeth are connected in opposite directions.
The armature C. and distributor D. are mounted on the same shaft and revolve
together. The motor armature is wound so that if there are w sections in the
armature, each section has two coils superposed there being in all 2 w coils, such as
1—1ª—2—2ª—3-3 etc.-the coils in pairs being wound in an opposite sense.
Each of these coils has in circuit with it one of the coils numbered correspondingly
on the distributor armature in Figure 2. As the figure shows the coils 1, 2, 3, 7, 8,
and 3 4 5 6 7 on the distributor are underneath the magnetic circuit-closer B.
and in these coils therefore the current will be small owing to the increased self
induction, whilst in the coils 4. 5. 6 and 8° 1 & 2" on the distributor the current
will be large. The effect of this is shown in Figure 1 in which the strongly energized
coils 2 1 8 6. 5. 4. are in a proper position to produce rotative energy and the
coils 2. 1. 8. 6ª 5ª 4" which are in a position in which they would otherwise retard
the said rotation are inoperative. The arrows indicate the corresponding direction of
current during some particular part of the phase and the result will be a rotation of
the armature in Figure 1.
The complete arrangement of circuit is as follows:-
The field magnets E. are wound in series or in shunt with the main alternating
supply circuit F. the said current entering the motor by the usual insulated collecting
ring G and brush or brushes g. The current is distributed in parallel to all the
distributing coils alike upon the distributor D. Figure 2 (one pair of coils only being
shown connected in the drawings by way of illustration).
From the said distributing coils the current is conducted to the correspondingly
numbered coils on the armature Fig. 1, which are not paired on the armature ring
Fig. 1. as they were on the distributor D. Fig. 2. The currents from the said
armature coils are returned direct to the second insulated collecting ring H. and
through a brush or brushes h. back to the main F.
Each pair of similarly numbered coils one upon the distributor D. and one upon
the armature C. is therefore in series between the one collecting ring or terminal C.
the other collecting ring or terminal H, and all the said pairs are connected each
individually in parallel between the said collecting rings or terminals of the mains.
Having now particularly described and ascertained the nature of my said inven-
tion and the manner in which the same is to be performed, I declare that what 1
claim is
1st. An electro-magnetic apparatus consisting of "impedence coils" provided with
a variable magnetic circuit for distributing or varying the current through one or
more external circuits.
2nd. The combination in an electric motor for alternating currents of a field magnet
system, an armature wound with duplicate and opposite coils or windings connected
to a distributor having a similar number of coils on it, the self induction of which is
different in different positions of the coils producing a distribution of electric current
in the armature coils, giving a uniform rotary effort.
The 7th daw of Ta1000
FELL & WILDING,
1, Queen Victoria Street, E.C., Agents for the Applicant.
FELL & WILDING,
1, Queen Victoria Street, E.C., Agents for the Applicant.