provements relating to the Operation of Electric Motors at Different Speeds.
Year: 1899

page_text: Date of Application, 2nd Mar., 1899
Complete Specification Left, 1st Dec., 1899-Accepted, 27th Jan., 1900
PROVISIONAL SPECIFICATION
Improvements relating to the Operation of Electric Motors at
Different Speeds.
I, CHARLES JOHN REED, of 3313, North Sixteenth Street, Philadelphia, in the
State of Pennsylvania, United States of North America, Electrical Engineer, do
hereby declare the nature of this invention to be as follows:
-
My invention relates to the operation of electric motors and has for its object
to provide an improved method of and means for operating these machines at
different speeds by current supplied from a divided source of electrical energy,
By the term divided source, I mean a source of energy consisting of two or more
independent units or sources capable of being united together in series or in
parallel or both, for example, a number of primary or secondary batteries, or a
number of dynamos, or batteries and dynamos, combined may be used. The
units should have equal electromotive force, and preferably also be of equal
capacity.
According to my invention I divide the field-magnet coils into sections, the
number of sections being preferably proportional to the number of units com-
posing the source of electrical energy, and I arrange that each section of the
coils shall be independently supplied with current from one or more of the units.
I further arrange that the armature of the electric motor shall be
supplied with current from the whole of the source of electrical energy,
the grouping of the units being varied SO as to vary the electro-
motive force of supply. Since the magnetic flux due to the current circulating
round the field-magnet coils is maintained constant, the variation in the electro-
motive force supplied to the armature will cause the motor to rotate at different
speeds.
In the accompanying drawings, I have shewn means for carrying my invention
into practical effect, the divided source of electrical energy consisting of a
number of secondary cells of substantially similar electromotive force and
capacity, each unit comprising two cells. It will be understood that I am not
restricted to these precise means, as other means may be used for practising my
improved method of operation.
Fig. 1 is a diagram of a motor, secondary battery cells, and a controller, the
drum of the latter being developed into a plane.
Figs. 2-5 represent diagramatically four different ways of connecting the
motor to the cells.
Fig. 6 is a front elevation and
Fig. 7 is a plan view of the controller shewn diagramatically in Fig. 1.

page_text: Fig. 8 is a diagram shewing a divided source of electrical energy connected to
two motors.
Fig. 9 is a diagram illustrating my invention in connection with a number of
motors, each of which has a single field winding.
Referring now to Figs. 1-5 of the drawings, the divided source of electrical
energy consists of six sets of secondary cells indicated at 1, 2, 3, 4, 5, 6: 7 is the
motor armature to which current is supplied by the brushes 8, 9: the field-
magnet coils are divided into six sections 10, 11, 12, 13, 14, 15, corresponding in
number to the six units of the source of energy. Each section of the field-
magnet coils is connected to the terminal of one unit of the source of energy as
shewn. Referring now particularly to Figs. 1, 16, 17 are contact terminals of a
pair of mains from which the secondary cells 1-6 can be re-charged when
necessary. 18, 19, are similar contact fingers connected to the brushes 8, 9 of the
motor armature. The sections 10-15 of the field-magnet coils are connected to
pairs of terminals 20-25, and the terminals of the units 1-6 of the source of
energy are respectively connected to contact fingers 26-31. During the opera-
tion of the motor, the terminals 20 and 26, 21 and 27 etc., are in contact, but
when the battery cells require to be re-charged said terminals are separated so as
to cut the field-magnet coils out of circuit. The controller drum indicated at 32
is provided with nine longitudinally arranged sets of contact plates or strips
marked A, B, C, D, E, F, G, H and K. The set marked A has plates in position
to engage the fingers 16, 17 and 26-31, the other eight sets have plates corre-
sponding to contacts 18, 19 and 26-31. The electrical connections between the
plates in a set are clearly shewn in the diagram Fig. 1. The mechanical con-
struction of the controller is shown in Figs. 6 and 7, the shaft 33 of the con-
troller drum having a disc 34 provided with notches 35 adapted to co-operate with
a spring pawl 36, said notches corresponding in position to the several sets of
contact strips A-K of the drum. The shaft 33 has also at or near each end a dise
or ring 37, having a notch 38, the said notches being adapted to engage with
rollers 39, secured pivoted to arms 40. These arms carry a rod 41 to which is
secured to a plate or strip of insulating material 42 adapted to engage between
the contact fingers 20 and 26, 21 and 27 etc., so as to separate the same and
insulate them respectively from each other when the rollers 39 are in the
notches 38. This is clearly seen from the plan: Fig. 7 which also shews the con-
tact 26 divided into two parts, one of which 43 is adapted to connect with the
terminal 20. and the other 26 being arranged to connect with the plates on the
surface of the controller drum. The strip 42 is provided with a series of metal
nieces, one of which is indicated at 44, for making contact between the contact
fingers 20 and 43, when the arms 40 are moved outward against the pull of the
spring 45. The plate 42 may obviously be replaced by a series of plates of
insulation, each having metallic pieces such as 44 and corresponding in number
to the contact fingers 20--25.
The operation of the controller is as follows:--
When the drum is in the position shown in Figs. 6 and 7, the roller 39 being
in the notch 38, the series of plates A are in contact with the series of contact
fingers 16, 17, and 26-31. The contact fingers 20 and 26, 21 and 27 etc., are
separated by the insulating strip 42, and consequently the battery 1-6 is con-
nected in series to the mains, from which it can be charged. If the controller
drum is rotated in the direction shewn in the arrow on Fig. 7, the plates 16, 17,
26-31. will be disconnected from the set of contacts A disconnecting the battery
from the supply, the roller 39 will be forced outward by the rings 37 thereby
causing the arms 40 to move out and connecting the contact fingers 20 and 26,
21 and 27 etc., through the medium of the metallic pieces thereby connecting the
field-magnet coils to the source of electrical energy and as the controller drum
is rotated the set of plates marked B will come in contact with the contact
fingers 18 and 26-31 and it will be readily seen from consideration of the con-
nections of these plates that the units 1-6 will be joined in parallel to the

page_text: brushes 8, 9 of the armature of the motor, consequently, the electromotive force
of one unit only will be applied to said armature and the motor will rotate at .
its minimum speed. This grouping of the source and motor is shewn in Fig. 2.
It will be seen that there is a considerable gap on the controller drum 32 between
the series of plates A and the series B, consequently, the field-magnet coils will
be connected to the source of energy before the armature is connected and the
field-magnet will thereby be enabled to build up its magnetism.
As the drum is rotated in the same direction the series of plates C will come
in contact with the contact fingers 18, 19, and 26-31, and it will be seen that
between the contact fingers 18 and 19 the cells will be joined, two in series and
three in parallel. This grouping of cells and motor is shewn in Fig. 3, and the
motor will rotate at a speed corresponding to the electromotive force of two units
of the source in series, that is to say, at about twice the speed of the first arrange-
ment.
If the rotation of the controller drum is continued in the same direction until
the plates of series D make contact with the fingers 18, 19, and 26-31, the units
will be joined to the motor armature, three in series and two in parallel, the
grouping being that shewn in Fig. 4, and the speed of the motor being thereby
rendered approximately three times that of the first described arrangement, and
when the series of plates E are in contact with the fingers 18 and 19, and 26-31,
the six units will be joined in series to the motor armature, and the motor will
rotate at its maximum speed, the grouping being shewn in Fig. 5. The motor
drum cannot be rotated further in this direction. If a reversal of the direction
of rotation of the motor is desired the controller is rotated backwards so as to
cause the series of contact plates F, G, H, K, to make contact with the fingers 18,
19, and 26-31, and it will be readily seen that the circuits made thereby and
consequently the rates of speed obtained will correspond to those above described
except that the armature circuit is reversed with reference to the source of
electrical energy.
•
In place of employing a second series of plates F, G, H, K, on the controller
drum an ordinary reversing switch may be used in the armature circuit of the
motor.
It will be clear that the variations in speed of the motor will be obtained
without disconnecting the field-magnet coils from the source of electrical energy
and it will be readily understood that the invention is not restricted to the
division of the source of energy into six units but that with a greater number of
units greater variations in speed may be obtained.
In Fig. 8 I have shewn two motors 46 and 47 with their armatures 48 and 49
connected in parallel and driven from a source of energy divided into eight units
marked 50-57. The field-magnet coils of each motor are divided into four
sections, each section being connected to the terminals of one unit of the source
of energy. By any suitable means (a controller, for example, such as shewn in
Figs. 6 and 7), the connections of the source of energy to the armatures may be
varied so that currents are supplied to said armatures at different electromotive
forces and different speeds of the motors thereby obtained. The armatures of the
motors can obviously be joined in series instead of being placed in parallel so
that a further variation in speed is obtained in a manner wellknown in the art.
In Fig. 9 I have shewn four motors 58, each of which has a single field wind-
ing 59, which are respectively supplied with electrical energy from separate
units 60, 61, 62, 63, of a suitable source of energy divided into four parts. The
armatures 64 of the motors are connected in parallel to the source of energy so that
the maximum electromotive force is applied to each armature. In order to obtain
variations in speed the connections of the units forming the source may be varied
by any suitable means without altering the connections between said units and
the field windings of the motors. It will be further understood that the grouping
of the armatures of the four motors may be varied if desired so that additional

page_text: variations in speed may be obtained, and the number of units forming the source
of electrical energy and the number of motors may obviously be greater or less
than the number shewn, the invention not being restricted in this respect.
W. P. THOMPSON & Co.,
822, High Holborn, London, W.C.,
Patent Agents for the Applicant.
Improvements relating to the Operation of Electric Motors at
Different Speeds.
I, CHARLES JOHN REED, of 3313, North Sixteenth Street, Philadelphia, in the
State of Pennsylvania, United States of North America, Electrical Engineer, 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:-
My invention relates to the operation of electric motors and has for its object
to provide an improved method of and means for operating these machines at
different speeds by current supplied from a divided source of electrical energy.
By the term divided source, I mean a source of energy consisting of two or more
independent units or sources capable of being united together in series or in
parallel or both, for example, a number of primary or secondary batteries, or a
number of dynamos, or batteries and dynamos combined may be used. The
units should have equal electromotive force, and preferably also be of equal
capacity.
According to my invention I divide the field magnet coils into sections, the
number of sections being preferably proportional to the number of units com-
posing the source of electrical energy, and I arrange that each section of the
coils shall be independently supplied with current from one or more of the units.
I further arrange that the armature of the electric motor shall be
supplied with current from the whole of the source of electrical energy,
SO as to vary the electro-
the grouping of the units being varied
motive force of supply. Since the magnetic flux due to the current circulating
round the field magnet coils is maintained constant, the variation in the electro-
motive force supplied to the armature will cause the motor to rotate at different
speeds.
In the accompanying drawings, I have shewn means for carrying my invention
into practical effect, the divided source of electrical energy consisting of a
number of secondary cells of substantially similar electromotive force and
capacity, cach unit comprising two cells. It will be understood that I am not
restricted to these precise means, as other means may be used for practising my
improved method of operation.
Figure 1 is a diagram of a motor, secondary battery cells, and a controller, the
drum of the latter being developed into a plane.
Figures 2 to 5 represent diagrammatically four different ways of connecting the
motor to the cells.
Figure 6 is a front elevation and
Figure 7 is a plan view of the controller shewn diagrammatically in Figure 1.
Figure 8 is a diagram illustrating my invention in connection with a number of
motors, each of which has a single field winding.
Referring now to Figures 1 to 5 of the drawings, the divided source of electrical
1

page_text: energy consists of six sets of secondary cells indicated at 1, 2, 3, 4, 5, 6. 7 is the
motor armature to which current is supplied by the brushes 8, 9; the field
magnet coils are divided into six sections 10, 11, 12, 13, 14, 15 corresponding in
number to the six units of the source of energy. Each section of the field
magnet coil is connected to the terminal of one unit of the source of energy as
shewn. Referring now particularly to Figure 1; 16, 17 are contact terminals of a
pair of mains from which the secondary cells 1 to 6 can be re-charged when
necessary. 18, 19 are similar contact fingers connected to the brushes 8, 9 of the
motor armature. The sections 10 to 15 of the field magnet coils are connected to
pairs of terminals 20 to 25, and the terminals of the units 1 to 6 of the source of
energy are respectively connected to contact fingers 26 to 31. During the opera-
tion of the motor, the terminals 20 and 26, 21 and 27 etc., are in contact, but
when the battery cells require to be re-charged said terminals are separated so as
to cut the field magnet coils out of circuit. The controller drum indicated at 32
is provided with nine longitudinally arranged sets of contact plates or strips
marked A, B, C, D, E, F, G, H and K. The set marked A has plates in position
to engage the fingers 16, 17 and 26 to 31, the other eight sets have plates corre-
sponding to contacts 18, 19 and 26 to 31. The electrical connections between the
plates in a set are clearly shewn in the diagram Figure 1. The mechanical con-
struction of the controller is shewn in Figures 6 and 7, the shaft 33 of the con-
troller drum having a disc 34 provided with notches 35 adapted to co-operate with
a spring pawl 36, said notches corresponding in position to the several sets of
contact strips A to K of the drum. The shaft 33 has also at or near each end a disc
or ring 37, having a notch 38 the said notches being adapted to engage with
rollers 39, secured to pivoted arms 40. These arms carry a rod 41 to which is
secured a plate or strip of insulating material 42 adapted to engage between
the contact fingers 20 and 26, 21 and 27 etc., so as to separate the same and
insulate them respectively from each other when the rollers 39 are in the
notch 38. This is clearly seen from the plan, Fig. 7, which also shews the con-
tact 26 divided into two parts one of which 43 is adapted to connect with the
terminal 20, and the other 26 being arranged to connect with the plates on the
surface of the controller drum. The strip 42 provided with a series of metal
pieces, one of which is indicated at 44 for making contact between the contact
fingers 20 and 43, when the arms 40 are moved outward against the pull of the
spring 45.
The plate 42 may obviously be replaced by a series of plates of
insulation, each having metallic pieces such as 44 and corresponding in number
to the contact fingers 20 to 25.
The operation of the controller is as follows:-
When the drum is in the position shewn in Figs. 6 and 7, the roller 39 being
in the notch 38, the series of plates A is in contact with the series of contact
fingers 16, 17, and 26 to 31. The contact fingers 20 and 26, 21 and 27 etc., are
separated by the insulating strip 42, and consequently the battery 1--6 is con-
nected in series to the mains, from which it can be charged. If the controller
drum is rotated in the direction shewn in the arrow on Fig. 7, the plates 16, 17,
26 to 31, will be disconnected from the set of contacts A disconnecting the battery
from the supply, the roller 39 will be forced outward by the ring thereby
causing the arms 40 to move out and connecting the contact fingers 20 and 26,
21 and 27 etc. through the medium of the metallic pieces thereby connecting the
field magnet coils to the source of electrical energy and as the controller drum
is rotated the set of plates marked B will come in contact with the contact
fingers 18 and 26-31 and it will be readily seen from consideration of the con-
nections of these plates that the units 1-6 will be joined in parallel to the
brushes 8, 9 of the armature of the motor, consequently, the electromotive force
of one unit only will be applied to said armature and the motor will rotate at
its minimum speed. This grouping of the source and motor is shewn in Figure 2.
It will be seen that there is a considerable gap on the controller drum 32 between
the series of plates A and the series B, consequently, the field-magnet coils will

page_text: be connected to the source of energy before the armature is connected and the
field-magnet will thereby be enabled to build up its magnetism.
As the drum is rotated in the same direction the series of plates C will come
in contact with the contact fingers 18, 19, and 26-31, and it will be seen that
between the contact fingers 18 and 19 the cells will be joined, two in series and
three in parallel. This grouping of cells and motor is shewn in Figure 3 and the
motor will rotate at a speed corresponding to the electromotive force of two units
of the source in series, that is to say, at about twice the speed of the first arrange-
ment.
'
If the rotation of the controller drum is continued in the same direction until
the plates of series 1) make contact with the fingers 18, 19, and 26-31, the units
will be joined to the motor armature, three in series and two in parallel, the
grouping being that shewn in Figure 4, and the speed of the motor being thereby
rendered approximately three times that of the first described arrangement, and
when the series of plates E are in contact with the fingers 18, 19, and 26-31
the six units will be joined in series to the motor armature and the motor will
rotate at its maximum speed, the grouping being shewn in Figure 5. The motor
drum cannot be rotated further in this direction. If a reversal of the direction
of rotation of the motor is desired the controller is rotated backwards so as to
cause the series of contact plates F, G, H, K, to make contact with the fingers 18,
19, and 26-31, and it will be readily seen that the circuits made thereby and
consequently the rates of speed obtained will correspond to those above described
except that the armature circuit is reversed with reference to the source of
electrical energy.
In place of employing a second series of plates F, G, H, K, on the controller
drum an ordinary reversing switch may be used in the armature circuit of the
motor.
It will be clear that the variations in speed of the motor will be obtained
without disconnecting the field magnet coils from the source of electrical energy
and it will be readily understood that the invention is not restricted to the
division of the source of energy into six units but that with a greater number of
units greater variations in speed may be obtained.
In Figure 8 I have shewn four motors 58, cach of which has a single field wind-
ing 59, which are respectively supplied with electrical energy from separate
units 60, 61, 62, 63, of a suitable source of energy divided into four parts. The
armatures 64 of the motors are connected in parallel to the source of energy so
that the maximum electromotive force is applied to each armature. In order to
obtain variations in speed the connections of the units forming the source may
be varied by any suitable means without altering the connections between said
units and the field windings of the motors. It will be further understood that
the grouping of the armatures of the four motors may be varied if desired so that
additional variations in speed may be obtained and the number of units forming
the source of electrical energy and the number of motors may obviously be
greater or less than the number shewn, the invention not being restricted in
this respect.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
1 claim is:-
1. A controller for electric motors having a rotatable drum provided with sets
of contact plates or strips adapted to connect with fixed contact terminals when
the drum is rotated; said contact terminals being connected respectively to leads
from several units composing a source of electrical energy, and to the armature
terminals and the motor or motors, the connections of the sets of plates of the
controller drum being so arranged that the grouping of the units with reference
to the armature terminals is varied as the drum is rotated.
2. A controller for electric motors provided with means whereby the field-

page_text: magnet coils of the motor will be disconnected from the source of electrical energy
when the controller drum is rotated to a certain predetermined position, for the
purpose specified.
3. A controller having contact strips mounted on the drum, so arranged that a
divided source of electrical energy is connected in such a manner that it may
receive current from an exterior source of supply when the motor is not in
operation, and that when the motor is placed in operation the exterior source of
supply is first cut off and the field-magnets energised prior to current being
supplied to the armature.
4. Controllers for electric motors constructed and operating substantially as
described with reference to Figures 1 to 7 of the accompanying drawings.
5. The system for operating a number of electric motors at variable speeds
which consists in supplying a constant current to the fields of the motors and
varying the connections of the armatures, substantially as described with reference
to Figure 8 of the accompanying drawings.
Dated the First day of December 1899.
W. P. THOMPSON & Co..
Of London, Liverpool, Manchester and Birmingham.