of and Apparatus for Starting Non-synchronous Single-phase Alternating Current Motors.
Year: 1892

page_text: Date of Application, 30th Dec., 1892
Complete Specification Left, 24th July, 1893-Accepted, 26th Aug., 1893
PROVISIONAL SPECIFICATION.
Method of and Apparatus for Starting Non-synchronous Single-phase
Alternating Current Motors.
I, CHARLES EUGEN LANCELOT BROWN of Baden, Switzerland, Engineer and
Manufacturer, do hereby declare the nature of this invention to be as follows:-
The object of the present invention is to effect in a simple manner and without
requiring excessive current, the starting with considerable torque of non-synchronous
single-phase alternate current motors, that is motors consisting principally of two
windings namely an inducing winding connected directly with the mains and an
induced winding short circuited on itself and deriving its current by induction from
the former winding. For the purpose of reducing the magnetic resistance and
therefore the exciting current to a minimum, both windings are either sunk in holes
in the laminated iron cores with which both are provided, or in notches cut in the
surfaces, of the same, which notches may advantageously be completely closed by a
winding of iron wire, or partly so by projections from their sides.
The winding on the inducing part is arranged to give any suitable number of
poles but there are no projections on the iron where these occur, the iron being
perfectly uniform all round and the holes being equally disposed around the whole
circumference. Similarly on the induced part the winding is uniformly distributed
over its surface entirely independently of the poles in the inducing part. These
conditions are necessary in order to produce a motor which shall run non-
synchronously, and further, are of the greatest importance in enabling it to be
started by the method hereinafter described.
The starting of such a motor is effected according to this invention by destroying
the equilibrium of the forces set up between the inducing and induced parts of the
motor when the current is switched on whilst the motor is at rest. This may be
done in various ways.
For example, owing to the fact that different self inductions
produce differences of phase, the motor may be constructed with double windings
in such a way that besides that always required for the motor a second winding of
greater or less self induction is employed, which in a two pole arrangement is
placed at an angle of 90° from the first one. By this means when the windings are
placed in circuit with an alternating current generator a rotary field is produced
which overcomes the neutral state and causes the rotary portion of the motor to
start.
An arrangement for this purpose is shown diagrammatically in Fig. 1 according
to which the above mentioned difference of self inductions is produced by a drum
winding T and a ring winding R. L L represent the mains J the inductor, and
A the motor armature with a short circuited winding.
Either the ring or the drum winding may be used as the principal winding, it
being noted that that used only for starting may be of smaller cross section than
the other, since it remains in circuit for short periods only. As soon as the motor
has reached its proper speed, and in some cases even sooner, the starting winding
may be switched out.
Fig. 2 shows another way of obtaining difference of phase according to which
the greater self-induction of one winding say (R), is obtained by means of a
choking coil S placed in series with it but quite separate from the motor. In this
case the effect may be increased by making the other winding Ta drum winding.
The same object may be attained by the arrangement shown in Fig. 3. In this
case a device consisting for example of an ordinary condenser or preferably of a
number of cells Z having a large electrical capacity is shown inserted in series with
one of the windings.

page_text: The remarks made with regard to Fig. 1 apply equally to the arrangement shown
in Figs. 2 and 3.
Fig. 4 is a front elevation; and Fig. 5 a side elevation partly in section showing
another arrangement for starting a motor of the kind referred to. The induced
part of the motor, which in this case is again arranged to rotate has a winding
similar to that in direct current machines with the ends of the coils connected to a
collector C. Two opposite points of the winding are also connected to contact
rings N N.
Two brushes B B which are shown short circuited make contact with the
collector. In certain positions of these brushes with regard to the external field,
large currents are produced in the short circuited winding which produce poles,
which in consequence of the fixed position of the brushes remain in certain positions
with regard to the poles of the inducing field. A turning moment is thus produced
and the motor starts with a considerable torque. As soon as synchronism is
approached the brushes bb¹ on the contact rings are short circuited; the same
effect may also be produced by putting one broad brush across both rings.
The brushes B B may then be taken off the commutator and the motor will
continue to work synchronously with the rate of alternation of the current.
This arrangement may be subjected to various modifications. The connection
of the brushes B B, in particular, may be made in various ways some of which are
shown more particularly in the diagrams Figs. 6, 78 and 9.
In these figures L L are the mains, J J the inductor winding and A the rotary
induced part with the collector C, the brushes B B the contact rings N N and
the brushes bb. In the arrangement shown in Fig. 6, instead of directly short
circuiting the brushes B B, the winding on the rotary part is connected in parallel
with that on the fixed part.
This arrangement does not differ greatly from an ordinary direct current shunt
machine. The principal difference lies in the fact that the inductor winding has
a relatively very small resistance and that the iron cores, both inside and outside,
are laminated. A further difference lies in the fact that the magnetic field is of
the form which would be produced by the combination of the hole wound armatures
of two direct current machines.
By the passage of an electric current through the two windings, poles will be
produced in the fixed and rotating parts as described with reference to the
arrangement shown in Figs. 4 and 5, and by suitable adjustment of the brushes B B
these poles can be brought into such a position with regard to one another as
to cause the motor to instantly start. When the normal speed is reached, the
brushes bb are short circuited and by means of a switch K, the circuit BB is
opened. A resistance W serves to regulate the current at starting.
Fig. 7 shows a series arrangement of the inductor and the induced rotary part
wherein by means of a switch U the ordinary working connection can be made
after the motor has reached its full speed. The actions in this case are again
similar to those in the above described arrangements.
Fig. 8 shows an arrangement that differs from the arrangement described with
reference to Fig. 6 in that the rotary part is connected as shunt to a certain
number of turns of the inductor winding only.
Fig. 9 is a diagram of connections similar to those more fully described with
reference to Figs. 4 and 5 but with the difference that resistances W and to are
inserted between the brushes bb as well as between B B thus allowing of a certain
amount of regulation.
Instead of employing the usual winding of the induced part as described with
reference to Figs. 4 and 5, diametrically arranged wires, may also, for example, be
connected to opposite segments of the collector without being in connection with
the rest of the winding.
Furthermore the winding may be so arranged that all the wires are connected
together at the end remote from the collector but at the other end are directly
connected with such collector. Instead of only two diametrically opposite points

page_text: being short-circuited after synchronous rotation has been obtained all the
segments of the collector may be advantageously connected together either by a
contact arranged to press on the side, or by slipping a conducting ring over the
whole collector.
As will be obvious in all cases the inducing part may be arranged to rotate and
the induced part be fixed. The slight differences of construction then necessary
will be readily understood by persons skilled in the art to which this invention
relates.
Dated this 30th dex of December 1800
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Method of and Apparatus for Starting Non-synchronous Single-phase
Alternating Current Motors.
1, CHARLES EUGEN LANCELOT BROWN, of Baden, Switzerland, Engineer and
Manufacturer, 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 :-
The object of the present invention is to effect in a simple manner and without
requiring excessive current, the starting with considerable torque of non-synchronous
single-phase alternate current motors, that is motors consisting principally of two
windings namely an inducing winding connected directly with the mains and an
induced winding short circuited on itself and deriving its current by induction from
the former winding. For the purpose of reducing the magnetic resistance and
therefore the exciting current to a minimum, both windings are either sunk in
holes in the laminated iron cores with which both are provided, or in notches
cut in the surfaces of the same, which notches may advantageously be completely
closed by a winding of iron wire, or partly so by projections from their sides.
The winding on the inducing part is arranged to give any suitable number of
poles, but there are no projections on the iron where these poles occur, the iron
being perfectly uniform all round and the holes being equally disposed around the
whole circumference. Similarly on the induced part, the winding is uniformly
distributed over its surface entirely independently of the poles in the inducing part.
These conditions are necessary in order to produce a motor which shall run non-
synchronously, and further, are of the greatest importance in enabling it to be
started by the method hereinafter described.
The starting of such a motor is effected according to this invention by destroying
the equilibrium of the forces set up between the inducing and induced parts of the
motor when the current is switched on whilst the motor is at rest. This may be
done in various ways. For example, owing to the fact that different self inductions
produce differences of phase, the inducing part of the motor may be constructed
or provided with double windings in such a way that besides that always required
for the motor, a second or additional winding of greater or less self induction, is
employed, which in a two pole arrangement is placed at an angle of 90° from the first
one and is only brought into action for starting. By this means when the windings
are placed in circuit with an alternating current generator, a rotary field is produced
which overcomes the neutral state or equilibrium of the forces and causes the rotary
portion of the motor to start.
An arrangement for this purpose is shown diagrammatically in Fig. 1 of the
drawings filed with my Provisional Specification according to which the above
mentioned difference of self inductions is produced by a drum winding T and a ring
winding R. LL represent the mains, J the inductor, and A. the motor armature
with a short-circuited winding.

page_text: Either the ring winding R or the drum winding T, may be used as the principal
winding, it being noted that that used only for starting may be of smaller cross section
than the other, since it remains in circuit for short periods only. As soon as the motor
has reached its proper speed, and in some cases even sooner, the starting winding
may be switched out.
In this
Fig. 2 shows another way of obtaining difference of phase, according to which
the greater self-induction of one winding, say (R), is obtained by means of a
choking coil S placed in series with it but quite separate from the motor.
case the effect may be increased by making the other winding Ta drum winding.
The same object may be attained by the arrangement in Fig. 3.
In this case a
device consisting for example of an ordinary condenser or preferably of a number
of electrolytic cells Z having a large electrical capacity is shown inserted in series
with one of the windings.
The remarks made with regard to the windings used in Fig. 1 apply equally to
the arrangements shown in Figs. 2 and 3.
Fig. 4 is a front elevation; and Fig. 5 a side elevation, partly in section, showing
another arrangement for starting a motor of the kind referred to. The induced
part of the motor, which in this case is again arranged to rotate, has a winding
similar to that used in direct current machines (for example a Siemens or Gramme-
winding) the ends of the coils composing said winding being connected to a com-
mutator C. Two opposite points of the said winding are also connected to contact
rings N N, provided with brushes bb.
Two brushes B B which are shown short circuited in Fig. 4 make contact with the
commutator. When the inducing winding is switched into circuit not only will
currents be inducing in the whole of the induced winding but in certain positions of
the brushes B B with regard to the external field, large currents will be produced in
the short circuited winding producing poles, which, in consequence of the fixed
position of the brushes, remain in certain positions with regard to the poles of
the inducing field. A. turning moment is thus produced, and the motor starts
with a considerable torque.
An energetic starting may also be obtained by displacing relatively to each
other, two connected brushes arranged to bear against the commutator. In starting,
these brushes, lying side by side, are gradually moved away from each other until
they take up positions diametrically opposite to each other, supposing that the
arrangement has two poles, whereby large currents are induced in the short
circuited winding as before and the required turning moment produced. In each
case as soon as synchronism is approached, the brushes b, b' on the contact rings N N
are short circuited; the same effect may also be produced by putting one broad
-brush across both rings.
The brushes B B are then taken off the commutator and the motor will continue
to work nearly synchronously with the rate of alternation of the current.
This arrangement may be variously modified. The connection of the brushes B B,
in particular, may be made in various ways some of which are shown more particularly
in the diagrams Figs. 6, 7, 8 and 9.
In these figures LL are the mains, J J the fixed inductor winding and A the
rotary induced part with the commutator C, the brushes B 'B, the contact
rings N N and the brushes b b . In the arrangement shown in Fig. 6, instead of
directly short circuiting the brushes B B, the winding on the rotary part is
connected through them in parallel with that on the fixed part.
This arrangement does not differ greatly from an ordinary direct current shunt
machine. The principal difference lies in the fact that the inductor winding has a
relatively very small resistance and that the iron cores, both inside and outside,
are laminated. A further difference lies in the fact that the magnetic field is of
the form which would be produced by the combination of two direct current
armatures carrying the windings in holes.
By the passage of an electric current through the two windings, poles will be
produced in the fixed and rotating parts as described with reference to the

page_text: arrangement shown in Figs. 4 and 5 and by suitable adjustment of the brushes BB
these poles can be brought into such a position with regard to one another as to
cause the motor to instantly start. When the proper or normal speed is reached,
the brushes bb are short circuited and by means of a switch K, the circuit through
the brushes BB is opened. A resistance W with suitable switches, serves to
regulate the current in the rotary part at starting.
Fig. 7 shows a series arrangement of the fixed inductor and the induced rotary
part, wherein by means of a two-way switch U the rotary part can be put in series
before starting, and afterwards cut out of circuit and the ordinary working
connection inade, when the motor has reached its proper speed. The actions in
this case are again similar to those in the above described arrangements.
Fig. 8 shows an arrangement that differs from the arrangement described with
reference to Fig. 6 in that the rotary part is arranged to be connected by the
switch K as a shunt to a certain number of turns of the inductor winding only.
Fig. 9 is a diagram of connections similar to those more fully described with
reference to Figs. 4 and 5 but with the difference that resistances W and w
respectively are inserted between the brushes B B and between the brushes b, b,
thus allowing of a certain amount of regulation.
Instead of employing the usual winding of the induced part in the manner
described with reference to Figs. 4 and 5 additional coils or diametrically arranged
wires for starting may also, for example, be connected to opposite segments of the
commutator without being in connection with the rest of the winding.
Furthermore the winding may be so arranged that all the wires are connected
together at the end remote from the commutator but at the other end are directly
connected with such commutator. Instead of only two diametrically opposite
points being short-circuited after nearly synchronous rotation has been obtained, all
the segments of the commutator may advantageously be connected together either
by a contact arranged to press on the ends, or by slipping a conducting ring over the
whole commutator so as to bear against the whole of the commutator strips.
As will be obvious in all cases the inducing part may be arranged to rotate and
the induced parts be fixed. The slight differences of construction then necessary
will be readily understood by persons skilled in the art to which this invention
relates.
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. The herein described method of starting a non-synchronous single-phase
alternating current motor which consists in destroying the equilibrium of the forces
set up between the inducing and induced parts of the motor when the current is
switched on whilst the motor is at rest by causing a current to flow temporarily
through an additional winding arranged at an angle to the main or working
winding as set forth.
2. A non-synchronous single-phase alternating current motor having a winding
distinct from and additional to the main or working winding the two windings
having different self inductions substantially as herein described for the purpose
specified.
3. A non-synchronous single-phase alternating current motor having a winding
distinct from and additional to the main or working winding and a device or
devices offering resistance, self-induction or capacity for the purpose of producing
a difference of phase between the current in the additional winding and that in the
main winding, substantially as described.
4. For the purpose of starting a non-synchronous single-phase alternating
current motor, a commutator connected with the induced winding of the motor,
and provided with suitable brushes by the adjustment of which and their
5 connections either amongst themselves or with the external circuit, poles are

page_text: produced in the induced part which, owing to their position with regard to the
inducing part, produce a turning moment, substantially as described.
5. Single phase alternating current motors constructed arranged and operating
substantially as hereinbefore described with reference respectively to and shown in
Fig. 1 in Fig. 2; in Fig. 3; in Figs. 4 and 5; in Fig. 6; in Fig. 7; in Fig. 8; 5
and in Fig. 9 of the drawings annexed.
Dated this 24th day of July 1893
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.