Improvements in Alternating Current Motors.
Year: 1892

page_text: Date of Application, 12th Nov., 1892
Complete Specification Left, 14th Aug., 1893--Accepted, 23rd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Alternating Current Motors.
A communication from THE MASCHINENFABRIK OERLIKON, of Oerlikon, near
Zurich, Switzerland, Engineers.
I, WILLIAM LLOYD WISE, of 46 Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare the
nature of this invention to be as follows:-
This invention relates to a construction of electro motor designed to work with
a one-phase alternating current, and in which none of the exciting or field magnet
coils or the inductive coils of the armature need to be different as respects the
dimensions of their conductors or of their iron cores.
The
According to this invention the exciting or inducing coils are annularly arranged
after the manner of the winding of a Gramme-ring or drum armature or they may
be arranged in conjunction with polar projections or parts in such a manner that
north and south poles are formed alternately around the ring. The armature or
inductive coils consist of conductors which form either a number of short circuits
or coils closed upon themselves and independent of one another, or a number of
circuits electrically connected with one another and in which the alternating currents
induced by the exciting coils or by parts thereof circulate as active currents.
windings of the armature may be arranged according to any desired or approved
system of winding. On rotary motion being imparted to the machine in any
suitable manner, currents will be induced in those conductors of the armature which
are approaching one pole of the exciting coils and moving away from the opposite
neighbouring pole, these currents being less strongly repelled by the first pole then
by the second pole because, in consequence of the rotation, a given conductor will
assume a phase which in the position of rest, would belong to a conductor located
further back. The difference between the re-action of two successive poles upon
the intermediate conductors of the armature, has a tendency to increase the speed
of the motor until the motor runs synchronously, that is to say until it makes as
many revolutions in a second as the exciting current executes polar changes
multiplied by half the number of the poles of the exciting coils. At this speed
each conductor of the armature is subjected at every instant to an approximately
equal electro magnetic action of the exciting poles; consequently no current will
be generated in it. If the speed of the motor should cease to synchronize with the
exciting current there is produced between the inductive and induced coils a
turning moment which places itself in equilibrium with the turning moment of the
load on the machine.
The motor starts to run synchronously or nearly so after a certain initial speed
has been imparted to it. As soon as the motor is thus started, any variation of the
load up to full load can be made.
Any suitable means may be provided to start the motor when loaded.
A convenient arrangement for this purpose is as follows:-
On the ring of exciting coils there are arranged windings which can, during the
starting, be arranged in parallel with the exciting coils or can of themselves forin
a closed circuit. As soon as the loaded motor is started the circuit of these
windings is interrupted, or the windings are then placed in series with the exciting
coils. The action of these windings, which may be arranged to fill a gap between
two successive exciting coils or to surround a part of the exciting coils, consists
in that currents are produced in them which have a difference of phase with
respect to the currents of the adjacent exciting coils, that is smaller than 180°.

page_text: When these windings are coupled up in parallel with the exciting coils the
principle of this starting arrangement reduces itself to the following. The employ-
inent in an alternating current motor wound according to Tesla's arrangement for
two phase currents, of a one phase current only for starting, and to the cutting out
of this current as soon as the motor is started. This difference of phase causes a
turning moment between the inductive and induced coils. The motor can be
supplied with a speed regulator which places these starting windings in circuit, or
closes them upon themselves when the number of revolutions of the motor falls
below a certain limit.
The system of winding is explained by Figs. 12 and 3 of the accompanying
drawings in which
Fig. illustrates a motor in which two exciting coils are arranged after the
manner of the Gramme winding to produce two poles. The armature J is wound
with twelve closed coils.
Figs. 2 and 3 illustrate a similar motor in which the exciting coils are also
arranged to produce two poles. The armature J has twelve closed coils which
can be electrically connected together. The thick lines indicate the starting
windings which are either by means of the switch coupled up in parallel with the
exciting coils for the purpose of starting the motor (Fig. 2) or are closed upon
themselves (Fig. 3) and remain out of circuit so long as the motor is running at
the proper speed.
Dated this 12th day of November 1892.
W. LLOYD WISE,
Per F. J. Brougham,
COMPLETE SPECIFICATION.
Improvements in Alternating Current Motors.
A communication from THE MASCHINENFABRIK OERLIKON, of Oerlikon, near
Zurich, Switzerland, Engineers.
I, WILLIAM LLOYD WISE, of 46 Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, 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 a construction of electro motor designed to work with a
one-phase alternating current, and in which neither the exciting or field magnet
coils nor the inductive coils of the armature need to be respectively different among
themselves as respects the dimensions of their conductors or of their iron cores.
According to this invention, the exciting or inducing coils are annularly arranged
after the manner of the winding of a Gramme-ring or drum armature without
limited polar projections, that is to say a Gramme-ring armature, or drum armature
provided with a toothed or recessed iron core in such a manner that north and
south poles are formed alternately around the ring or drum. The armature or
inductive coils consist of conductors which form either a number of short circuits or
coils closed upon themselves and independent of one another, or a number of
circuits electrically connected with one another and in which the alternating
currents induced by the exciting coils, or by parts thereof, circulate as active
currents. The windings of the armature may be arranged according to any desired
or approved system of winding. On rotary motion being imparted to the machine
in any suitable manner, currents will be induced in those conductors of the armature
that are approaching one pole of the exciting coils in a two pole machine, and
moving away from the opposite neighbouring pole, these currents being less
strongly repelled by the first pole than by the second pole, because, in consequence
of the rotation, a given conductor will assume a phase, which, in the position
of rest, would belong to a conductor located further back. In the rotary motor
there are thus produced in the various conductors induced currents of different

page_text: phases. The difference between the re-action of two successive poles upon the
intermediate conductors of the armature, has a tendency to increase the speed
of the motor until the motor runs synchronously, that is to say, until it makes as
many revolutions in a second as the exciting current executes polar changes
At this speed
multiplied by half the number of the poles of the exciting coils.
each conductor of the armature is subjected at every instant to an approximately
equal electro magnetic action of the exciting poles, consequently the minimum of
current will be generated in it. If the speed of the motor should cease to
synchronize with the exciting current there is produced between the inductive and
induced coils a turning moment which places itself in equilibrium with the turning
moment of the load on the machine.
The motor thus starts to run synchronously, or nearly so, after a certain initial
speed has been imparted to it. As soon as the motor is thus started, any variation
of the load up to full load can be made.
Any suitable means may be provided to start the motor.
A convenient arrangement for this purpose is as follows:-
On the ring of the exciting coils there are arranged other windings which can,
during the starting be placed in parallel with the exciting coils, or can of themselves
form a closed circuit. As soon as the motor is started, the circuit of these windings
is interrupted, or the windings are then placed in series with the exciting coils.
The action of these windings, which may be arranged to fill a gap between two
successive exciting coils, or to surround part of the exciting coils, consists in that
currents are produced in them, having a difference of phase, with respect to the
current of the adjacent exciting coils, that is smaller than 180°. The difference of
phase can be increased by inserting a resistance in the new circuit and inserting an
induction coil in the other circuit.
When the said windings are coupled up in parallel with the exciting coils, the
principle of this starting arrangement reduces itself to the employment in an alter-
nating current motor, wound according to Tesla's arrangement for two phase
currents, of a one phase current only for starting, and to the cutting out of this
current as soon as the motor is started. This difference of phase causes a turning
moment between the inductive and induced coils. The motor can be supplied with
a speed regulator which places these starting windings in circuit, or closes them upon
themselves when the number of revolutions of the motor falls below a certain
limit.
The system of winding alternating current motors according to this invention
is explained by Figs. 1, 2 and 3 of the drawings, filed with my Provisional
Specification.
Fig. 1 illustrates a motor in which two exciting coils are arranged after the
manner of the Gramme winding to produce two poles. The armature J is wound
with twelve closed coils.
Figs. 2 and 3 illustrate a similar motor in which the exciting coils are also
arranged to produce two poles. The armature J has twelve closed coils which
The thick lines indicate the starting
cau be electrically connected-together.
windings, which are either coupled up in parallel with the exciting coils by means
of the switch for the purpose of starting the motor (Fig. 2), or are closed upon
themselves (Fig. 3) and remain out of circuit, so long as the motor is running at the
proper speed.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. A single-phase alternating current motor having a series of exciting or
inducing coils so arranged as to form an annular series of alternately north and
south poles, each pole being composed of a series of similar poles of the same sign,
and each pole being formed by an equal number of like coils connected in series or
parallel, and a series of armature or inductive coils consisting of two or more short

page_text: circuited conductors which may be electrically connected together, or be arranged
independently of each other, the arrangement being such that when the two series
of coils are rotated relatively to each other, there will be induced in the conductors
of the armature or inductive coils, currents of different phases, and the total
electro magnetic effect of which upon the exciting poles, represents a value different
from zero as soon as the motor has acquired a certain initial speed substantially as
described.
2. In a motor of the kind specified in the preceding claim, a device for starting
the motor, said device consisting of wire specially wound upon the inducing part of
the motor in a suitable position near the exciting coils and connected with a
switch for the purpose of utilising this special coil when the motor is being started,
that is to say, before it has assumed a practically synchronous speed of motion, by
forming in conjunction with the exciting coils of the motor, a rotary field in the
inductive part, and after the starting of the motor, or after switching off the
current, the special wire can be used as a portion of the exciting coils substantially
as described.
Dated this 14th day of Act 1902
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.