Year: 1898

page_text: Date of Application (in United Kingdom), 30th Aug., 1898
E. HARRY PHILLIPS DAVIS, of 327, Neville Street, Pittsburg, County of
Allegheny and State of Pennsylvania, U.S.A., Electrical Engineer, do hereby
declare the nature of this invention to be as follows:
My invention relates to controllers for electric motors and particularly to
that class of controllers employed for controlling the power and speed of railway
motors of large capacity.
The object of my invention is to provide a controller of the general character
above specified that shall embody means for varving the resistance of the
motor circuit through a wide range by comparatively small steps, at the same
time avoiding the injurious arcing that is liable to accompany the use of heavy
currents and also to so construct and combine the several parts of the mechanism
that they shall occupy a minimum amount of space and be so disposed as to
operate effectively and satisfactorily under all conditions of service.
In obtaining this object according to my invention I separate the switch for
varying the resistance in circuit with the motors from the switch for varying
the connections of the motors, the two switches being connected by gearing so
that the operation of the resistance varving switch will at the proper time cause
the second switch to alter the connections of the motors to series or parallel. or
rice versa.
Furthermore the resistance varving switch is so constructed that
the resistance is divided into sections, a portion of each section being cut in or out
simultaneously or nearly simultaneously, as the operating handle is revolved.
By this means the spark which occurs when very heavy currents are used is
divided up between a number of contacts instead of occurring at a single contact
only and the risk of burning the contact is considerably diminished.
My invention furthermore, comprises several constructional modifications here-
inafter fully pointed out.
In the accompanying drawing, Figure 1 is a front elevation of my controller, a
portion of the operating wheel being shewn in section.

page_text: Figure 2 is a front elevation of the operating parts of a controller adapted
for controlling two motors, the cover being removed.
Figure 3 is a similar view of a controller designed for controlling four motors.
Figure 4 is a transverse sectional view of the controller shewn in Figure 2, the
section being taken on line IV-IV of the said figure.
Figure 5 is a detailed view of a portion of the gearing embodied in the con-
troller shewn in Figures 2 and 4.
Figure 6 is a sectional view taken on line VI--VI of Figure 3.
Figure 7 is mainly a plan view of the controller shewn in Figure 3, the shafts
and frame being, however, shewn in section.
Figure 8 is a sectional view taken on line VIII-VIII of Figure 3.
Figures 9, 10 and 11 are detail views of certain portions of the interlocking
mechanism.
Figure 12 is a diagram of the circuits of the form of controller shewn in
Figures 2 and 4; and Figure 13 is a diagram shewing the relation of the motors
and resistance for the four principal running positions.
Figure 14 is a diagram of the circuits of the controller shewn in Figures 3, 6,
7 and 8, and Figure 15 is a diagram shewing the relation of the motors and
resistances for the three principal running positions.
I will first describe so much of the controller as is common to both of the
modifications illustrated in the drawings, reference being had particularly to
Figures 1, 2 and 3. The base or frame 1 of the controller may be supported in
position in the usual manner, preferably upon or adiacent to the dashboard of
the car, and suitably hinged or otherwise fastened to the same is a cover 2 for the
operating parts of the controller. The controller operating shaft 3 is squared at
its outer end and on such squared end is fitted an operating wheel 4 provided
with spokes. 4 and handles 5.
Surrounding the shaft 3, but immovably supported upon the base 1 is the
stationary member 6 of the resistance-varying switch, this member 6 being
provided with four groups or sets of contact strips or plates 7, to which are
permanently connected the resistance coils R. Rigidly mounted upon the shaft 3
is a head 8 having four arms 9, the outer end of each of which supports a contact
brush 10 adapted to make contact with the several stationary contact plates or
strips 7 as the shaft 3 is rotated.
In order to insure a step by step movement of the contact brushes 10 I provide
a ring 11 with notches 12 therein corresponding to the respective positions
where it is desired to make temporary steps in the revolution of the brushes 10.
A lever 13 is pivoted to one of the arms 9, one end of which is normally pressed
towards the notched edge of the ring 11 by a spring 14. A lever 15 is pivoted
in a suitable recess in the side of the shaft 3. one arm of which rests normally
against the end of a pin 16, extending through one of the spokes 4 of the
operating wheel 4.
The other end of the lever 15 is in position to engage the
inner end of a pin 17. the outer end of the pin 17 resting against one end of
the lever 13. It will be seen, therefore, that as the pin 16 is moved inwardly
by means of pressure applied to its outer end, the lever 15 will be rocked to
push the pin 17 out against one end of the lever 13 and thus move the other
end from the notch 12 in which it rests. If the pressure be removed from the
pin 16, the end of lever 13 will obviously drop into the next notch and stop
further rotation until the spring 16 is again pressed inward. 18 is a stop piece
or projection carried by the head 8 and engaging with a stationary shoulder or
abutment 19, when the brushes are in the initial or zero position indicated in
Figure 2 of the drawings.
The inner end of shaft 3 is provided with a beveled gear wheel or gear
segment 20 that meshes with a beveled pinion 21 on one end of a shaft 22
mounted in suitable hearing parallel to the base or back frame of the controller.
In the form of controller shewn in Figures 2, 4, and 5. the shaft 3 is also
provided with a beveled gear segment 20 arranged to mesh with a pinion

page_text: segment 21" on the shaft 22 during a portion of the rotation of the shaft sub-
sequent to the portion in which the segment 20 engages with the segment 21.
The radius of the segment 20" being very much greater than that of the seg-
ment 20, the engagement of the former with the segment 21" will obviously
serve to rotate the shaft 22 at a materially greater speed than is effected by the
engagement of the segment 20 with the pinion 21, assuming that there is no
change in the speed of rotation of the shaft 3. The reason for this construction
will be hereinafter more fully set forth.
The other end of the shaft 22 is provided with a pinion 23 that meshes with a
gear segment 24 mounted upon a shaft 25, the diameter of the segment 24
being materially greater than that of the pinion 23 for reasons that will be
hereinafter explained.
Rigidly mounted upon the shaft 25 is a drum d provided with contact plates
or strips arranged, in the controller shewn in Figure 2, in the manner indicated
in Figure 12, and in the controller shewn in Figure 3, in the manner indicated
in Figure 14.
Arranged at one side of the drum d is a series of contact fingers m and at the
other side a series of contact fingers m', these being connected in circuit in a
manner to be described, so that the position of the drum d will determine the
circuit connections of the motors with reference to each other.
at
one
2"
a
In Figures 2 and 4 the reversing switch for the motors is shewn
at the right and comprises શ drum co-operating contact fingers
at
side and corresponding fingers
the other side and
gear segment 26 with which meshes a gear segment 27, the latter being
rigidly mounted upon a rod 29 projecting out through the frame of
the machine and provided with a squared end to which may be fitted an operating
handle. The shaft 29 has also rigidly fastened upon it a head 30 provided
with three notches 31, the middle one of which is a greater distance from the
shaft 29 than the other two, as is usual in interlocking mechanism. An arm 32
is rigidly mounted upon a shaft 33 at one end and is provided at its other end
with a roller in position to engage with any one of the notches 31 according to
the position of the head 30. Another short arm 34, rigidly mounted on the
shaft 33, is connected to the base of the controller by means of a coiled
spring 35, the latter co-operating with such arm to press the roller in the end
of arm 32 towards the nead 30. A locking lever 26 is rigidly mounted upon
the shaft 33 and projects inward in position to lock the shaft 3 against rotation
when the roller on the end of the arm 32 is in the middle notch 31 of the head 30.
At the other side of the series-parallel switch is a cut-out switch, embodying
a drum and co-operating contact fingers on one side, and on the other
side. The shaft 20% of this drum is provided with a geared segment 26" with
which meshes a geared segment 27" rigidly mounted upon a rod or shaft 29" that
projects outward through the frame and is provided with a squared end for the
reception of a handle, as is the case with the shaft or rod 29 at the other side
of the controller. This shaft 29 has also rigidly fastened to it a head 30"
provided with notches 31" with which co-operate an arm 32", shaft 33, armı 34",
spring 35", and lever 36", all substantially like the corresponding parts located
at the other side of the controller and heretofore described, except that the
arms 35 and 36 have inner ends of different shape as shown in Figures 9 and 10.
When the roller on the arm 32" is in the middle notch on the head 30", the
shaft 3 is locked against rotation, and when such roller is in one of the side
notches, one of the motors is cut out of circuit, and when in the other side
notch, the other motor is out of circuit.
This will be understood by referring to Figures 9 10 and 11, in which are
shewn the locking devices. 37 is a sleeve pinned to shaft 3 and provided with
a notch 37 on one side and a wider notch 37 on the other side. The sleeve 37
is also provided with an annular groove 38. Below the sleeve 37 is a guide 39
for the ends of levers 36 and 36°, this guide being loose upon shaft 3.
When the

page_text: roller on arm 32 is in the middle notch 31 in head 30, the free end of arm 36
is in the position shewn in Figure 9, the shaft 3 is locked against rotation, but
when it is in either of the side notches, the end of arm 36 is in groove 38
and the shaft is free to rotate. When the roller on arm 32" is in the middle
notch 31, neither motor is cut out and the end of arm 36" is in the groove 38, as
is indicated in Figure 9, but when it is in either of the side notches, the end of
arm 36" is raised into the wide notch 37b and the shaft 3 is permitted to rotate
enly a distance corresponding to a series connection of the motors.
The operation of this controller and the relation of the several co-operating
parts and the circuits will be more readily understood by referring to Figures 12
and 14.
When the brushes 10 are in the respective positions indicated in Figure 2,
these positions being designated in Figures 12 and 14 as u, u, u and u³, the
circuit is open. Assuming that the fingers m, m³, are respectively in contact with
the strips on the drum corresponding to positions s, s', that the brushes r, r,
are respectively in positions, ', on the drum d, and that brushes c, c', are in
the positions, on the drum d, if the brushes 10 be moved in the clockwise
direction to bring the same respectively into engagement with the first contact
pieces 7 of the respective sets, the curent will enter the controller from the
irolley or other current collecting device t, pass through all of the resistance R
and the motors M, M¹, in series to ground. As the brushes 10 are moved step
by step in the direction westward the resistance R will be cut out section by
section until the brushes 10 are respectively in positions v, vi, 2 and 3, when all
of the resistance will be cut out of circuit and the motors will be in series, as
indicated in the second position Figure 13. As the brushes move from left to
right from positions v, v, v2, v3 to positions u¹, us, u³, u, the resistance will be
cut in, section by section, and in passing over the insulating segments at u, u²,
u, u, the circuit will be interrupted. The length of the contact strips on the
drum d and the relation between the elements of the gearing between the two
switches are such that the fingers m, m² will pass on to the strips corresponding
to positions p, p, while the brushes are passing from points u, u², u³, u, to the
first contact pieces 7 of the next succeeding sets, and when this point is reached,
the motors are connected in parallel with all of the resistance in circuit. This
resistance is then gradually cut out by the movement of the brushes 10 until
the points, 1, 3, 3 are reached, when the motors will be in parallel without
resistance, as indicated in the third position in Figure 13. A further rotation
of shaft 3 a sufficient distance will bring gear segment 20ª (Figure 5) into mesh
with pinion segment 21", and thus quickly move drum d to bring fingers m and
m respectively into engagement with contact strips and was well as the
corresponding wider strips, at the same time the resistance will be cut into and
then out of circuit. In this final position the coils and are connected in shunt
to the respective field magnets f and f¹ of the motors M and M¹.
In order to reverse the current in the field magnet windings f and f¹ of the
motors, the drum & will be turned to bring the brushes rr, respectively into
positions y and y¹. The connections may be obviously made so as to reverse the
current in the armatures a and a', if desired. In order to cut out the motor M
the drum will be turned to bring the brushes cc respectively into positions ³
and 23, and to cut out motor m', the drum & will be rotated to bring the
brushes c respectively into positions, z³.
وتا
Referring now more particularly to the controller illustrated in Figure 3 and
Figures 6 to 11, the series parallel drum d is provided with a greater number of
contact strips for the reason that there are four motors and it is desired to
couple them in series, in series-parallel and in parallel, the series connection being
made when the brushes m are in contact with the strips corresponding to posi-
tions; the series-parallel connection, when the brushes m and m¹ are respec-
tively in contact with the strips corresponding to the positions sp and s¹ p¹; and
the parallel connection, when the brushes m and m₁ are respectively in contact_

page_text: with the strips corresponding to positions and p¹, the gearing between the
shaft 3 and the drum d being so proportioned that the change from
series to parallel and from series-parallel to parallel will occur when the circuit is
broken by the resistance varying switch, i.e., when the brushes of said switch are
in positions u, u, u² and u as has been already described in substance in con-
nection with the two motor controller.
In this controller, instead of employing a reversing switch at one side and a
cut out switch at the other, I employ two combined reversing and cut-out switches,
one at each side of the series parallel switch, and each comprising two drums ³
and , normally fastened to a single shaft 39 by means of a suitable locking
device 40, but independently detachable therefrom in order to cut out any one
of the motors.
The gearing for the reversing switch at one side is substantially the same as
that heretofore described in connection with the controller for two motors and
comprises a segment 41 rigidly mounted upon the shaft 39 and a gear segment 42
meshing therewith and rigidly mounted upon the rod 43. This rod 43 also
carries or is provided with a head 44 having the usual three notches 45 with
which co-operate arms 46 and 47, coiled spring 48, and the locking lever 36.
The reversing switch drums at the other side of the controller are operated
simultaneously with those operated directly by the mechanism above described,
the means for effecting this simultaneous operation comprising an arm 49 rigid
on each shaft 39 and a connecting link or bar 50 between the said arms.
In order to cut out any one of the motors, I provide for each cut-out drum a
cam-shaped plate 51 having a notch 52, the cam plates for the drums d being
located at the bottom and those for the drums at the top. Rigidly mounted
upon a shaft 53 at the rear of the right hand drums d³ and dare elbow levers 54,
the outer end of which respectively rest against the cam surfaces of the corre-
sponding plates 51. Each is pivotally connected by means of an arm 55 to one
end of a bar 56 and the latter is pivotally connected at its other end to an arm 57
rigid on a shaft 58 at the other side of the controller.
The shaft 58 is also provided with two elbow levers 54 to co-operate with the
cam. plate 51. The arm 36 is also rigidly connected to shaft 58. When any
one of the drums is unlocked from its shaft and turned from right to left, the
free end of the lever 36 will be raised into the groove 37b, thus preventing
movement of the shaft 3 beyond the position corresponding to a series connection
of the motors.
An auxiliary means for preventing operation of the controller beyond the
position corresponding to series connection of the motors comprises a
shaft or rod 63 provided with a notched head 64 and a crank pin 64",
the latter being located beneath one of the brushes 10 in Figure 3
A two-
and therefore not shewn in that figure (sec Figures 7 and 8).
armed
58 and
end
the free
of
upon shaft
lever
59--65 is loose
arm 65 is provided with a roller that engages with the notches in head 64.
The free end of arm 59 has one end of a rod 60 pivoted to it. The free end of
this rod is provided with a guide 61 and is moved outward to engage a stop 52
(see Figure 7) on the movable member of the switch by the action of crank
pin 64 upon a bifurcated lever 65 that is rigidly connected to lever 59-65, this
action taking place when the shaft 63 is turned to bring the roller on arm 65
into the outer notch in head 64.
Referring particularly to Figures 14 and 15, when the drums are in such
position that the fingers and rare respectively in positions and ¹, the
motors are connected for movement in one direction, and
when these
motors
brushes are respectively engaged in positions y and y, the
are connected for movement in the opposite direction. When any drum
is detached from its shaft and rotated to bring the brushes r and r respectively
into positions and ¹, the motor corresponding to this drum is cut out of
circuit.

page_text: Except as otherwise hereinbefore specified, the operation of this form of
controller is the same as that of the forin shewn in Figures 2, 4, 12 and 13.
Dated the 30th day of August 1898.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.
Improvement in Controllers for Electric Motors.
I, HARRY PHILLIPS Davis, of 327, Neville Street, Pittsburgh, County of
Allegheny and State of Pennsylvania, U.S.A., 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 controllers for electric motors and particularly to
that class of controllers employed for controlling the power and speed of railway
motors of large capacity.
The object of my invention is to provide a controller of the general character
above specified that shall embody means for varying the resistance of the
motor circuit through a wide range by comparatively small steps, at the same
time avoiding the injurious arcing that is liable to accompany the use of heavy
currents and also to so construct and combine the several parts of the mechanism
that they shall occupy a minimum amount of space and be so disposed as to
operate effectively and satisfactorily under all conditions of service.
In obtaining this object according to my invention I separate the switch for
varying the resistance in circuit with the motors from the switch for varying
the connections of the motors, the two switches being connected by gearing so
that the operation of the resistance varying switch will at the proper time cause
the second switch to alter the connections of the motors to series or parallel, or
vice versa. Furthermore the resistance varying switch is so constructed that
the resistance is divided into sections, a portion of each section being cut in or out
simultaneously or nearly simultaneously, as the operating handle is revolved.
By this means the spark which occurs when very heavy currents are used is
divided up between a number of contacts instead of occurring at a single contact
only and the risk of burning the contact is considerably diminished.
My invention furthermore, comprises several constructional modifications here-
inafter fully pointed out.
In the drawings filed with my Provisional Specification Figure 1 is a front
elevation of my controller, a portion of the operating wheel being shewn in
section.
Figure 2 is a front elevation of the operating parts of a controller adapted
for controlling two motors, the cover being removed.
Figure 3 is a similar view of a controller designed for controlling four motors.
Figure 4 is a transverse sectional view of the controller shewn in Figure 2, the
section being taken on line IV-IV of the said figure.
Figure 5 is a detailed view of a portion of the gearing embodied in the con-
troller shewn in Figures 2 and 4.
Figure 6 is a sectional view taken on line VI-VI of Figure 3.
Figure 7 is mainly a plan view of the controller, shewn in Figure 3, the shafts
and frame being, however, shewn in section.
Figure 8 is a sectional view taken on line VIII-VIII of Figure 3.

page_text: Figures 9, 10 and 11 are detail views of certain portions of the interlocking
mechanism.
Figure 12 is a diagram shewing the various electrical connections of the parts
of the controller shewn in Figures 2 and 4; and Figure 13 is a diagram shewing
the relation of the motors and resistances for the four principal running positions.
Figure 14 is a diagram similar to Figure 12 but relating to the controller
shewn in Figures 3, 6, 7 and 8, and Figure 15 is a diagram shewing the relation
of the motors and resistances for the three principal running positions.
I will first describe so much of the controller as is common to both of the
modifications illustrated in the drawings, reference being had particularly to
Figures 1, 2 and 3. The base or frame 1 of the controller may be supported in
position in the usual manner, preferably upon or adjacent to the dashboard of
the car, and suitably hinged or otherwise fastened to the same is a cover 2 for the
operating parts of the controller. The controller operating shaft 3 is squared at
its outer end and on such squared end is fitted an operating wheel 4 provided
with spokes 4* and handles 5.
Surrounding the shaft 3, but immovably supported upon the base 1 is the
stationary member 6 of the resistance-varying switch, this member 6 being
provided with four groups or sets of contact strips or plates 7, to which are
permanently connected the resistance coils R. Rigidly mounted upon the shaft 3
is a head 8 having four arms 9, the outer end of each of which supports a contact
brush 10 adapted to make contact with the several stationary contact plates or
strips 7 as the shaft 3 is rotated.
In order to insure a step by step movement of the contact brushes 10 I provide
a ring 11 with notches 12 therein corresponding to the respective positions
where it is desired to make temporary steps in the revolution of the brushes 10.
A lever 13 is pivoted to one of the arms 3, one end of which is normally pressed
towards the notched edge of the ring 11 by a spring 14. A lever 15 is pivoted
in a suitable recess in the side of the shaft 3, one arm of which rests normally
against the end of a pin 16, extending through one of the spokes 4ª of the
operating wheel 4. The other end of the lever 15 is in position to engage the
inner end of a pin 17, the outer end of the pin 17 resting against one end of
the lever 13. It will be seen, therefore, that as the pin 16 is moved inwardly
by means of pressure applied to its outer end, the lever 15 will be rocked to
push the pin 17 out against one end of the lever 13 and thus move the other
end from the notch 12 in which it rests. If the pressure be removed from the
pin 16, the end of lever 13 will obviously drop into the next notch and stop
further rotation until the pin 16 is again pressed inward. 18 is a stop piece
or projection carried by the head 8 and engaging with a stationary shoulder or
abutment 19, when the brushes are in the initial or zero position indicated in
Figure 2 of the drawings.
The inner end of shaft 3 is provided with a bevelled gear wheel or gear
segment 20 that meshes with a bevelled pinion 21 on one end of a shaft 22
mounted in suitable bearing parallel to the base or back frame of the controller.
In the form of controller shewn in Figures 2, 4, and 5, the shaft 3 is also
provided with a bevelled gear segment 20 arranged to mesh with a pinion
segment 21 on the shaft 22 during a portion of the rotation of the shaft sub-
sequent to the portion in which the segment 20 engages with the segment 21.
The radius of the segment 20 being very much greater than that of the seg-
ment 20, the engagement of the former with the segment 21 will obviously
serve to rotate the shaft 22 at a materially greater speed than is effected by the
engagement of the segment 20 with the pinion 21, assuming that there is no
change in the speed of rotation of the shaft 3. The reason for this construction
will be hereinafter more fully set forth.
The other end of the shaft 22 is provided with a pinion 23 that meshes with a
gear segment 24 mounted upon a shaft 25, the diameter of the segment 24

page_text: being materially greater than that of the pinion 23 for reasons that will be
hereinafter explained.
Rigidly mounted upon the shaft 25 is a drum d provided with contact plates
or strips arranged, in the controller shewn in Figure 2, in the manner indicated
in Figure 12, and in the controller shewn in Figure 3, in the manner indicated
in Figure 14.
Arranged at one side of the drum d is a series of contact fingers m and at the
other side a series of contact fingers m¹, these being connected in circuit in a
manner to be described, so that the position of the drum d will determine the
circuit connections of the motors with reference to each other.
a
In Figures 2 and 4 the reversing switch for the motors is shewn at the right and
comprises a drum & mounted on a shaft 28 with co-operating contact fingers r
at one side and corresponding fingers rl at the other side and
gear segment 26 with which meshes a gear segment 27, the latter being
rigidly mounted upon a rod 29 projecting out through the frame of
the machine and provided with a squared end to which may be fitted an operating
handle. The shaft 29 has also rigidly fastened upon it a head 30 provided
with three notches 31, the middle one of which is a greater distance from the
shaft 29 than the other two, as is usual in interlocking mechanism. An arm 32
is rigidly mounted upon a shaft 33 at one end and is provided at its other end
with a roller in position to engage with any one of the notches 31 according to
the position of the head 30. Another short arm 34, rigidly mounted on the
shaft 33, is connected to 'the base of the controller by means of a coiled
spring 35, the latter co-operating with such arm to press the roller in the end
of arm 32 towards the head 30. A locking lever 36 is rigidly mounted upon
the shaft 33 and projects inward in position to lock the shaft 3 against rotation
when the roller on the end of the arm 32 is in the middle notch 31 of the head 30.
At the other side of the series-parallel switch is a cut-out switch, embodying
a drum and co-operating contact fingers on one side and c¹ on the other
side. The shaft 28 of this drum 2 is provided with a geared segment 26* with
which meshes a geared segment 27" rigidly mounted upon a rod or shaft 29° that
projects outward through the frame and is provided with a squared end for the
recention of a handle, as is the case with the shaft or rod 29 at the other side
of the controller. This shaft 29ª has also rigidly fastened to it a head 30
provided with notches 31 with which co-operate an arm 32°, shaft 33", arm 34".
spring 35, and lever 36, all substantially like the corresponding parts located
at the other side of the controller and heretofore described. except that the
arm 36 and 36 have inner ends of different shape as shewn in Figures 9 and 10.
When the roller on the arm 32 is in the middle notch on the head 30°, the
shaft 3 is locked against rotation, and when such roller is in one of the side
notches, one of the motors is cut out of circuit, and when in the other side
notch, the other motor is out of circuit.
This will be understood by referring to Figures 9, 10 and 11, in which are
shown the locking devices. 37 is a sleeve pinned to shaft 3 and provided with
a notch 37 on one side and a wider notch 37b on the other side. The sleeve 37
is also provided with an annular groove 38. Below the sleeve 37 is a guide 39
for the ends of levers 36 and 36. this guide being loose upon shaft 3. When the
roller on arm 32 is in the middle notch 31 in head 30. the free end of arm 36
is in the position shewn in Figure 9. the shaft 3 is locked against rotation, but
when it is in either of the side notches, the end of arm 36 is in groove 38
and the shaft is free to rotate. When the roller on arm 32 is in the middle
notch 31, neither motor is cut out and the end of arm 36 is in the groove 38, as
is indicated in Figure 9. but when it is in either of the side notches, the end of
arm 36 is raised into the wide notch 37b and the shaft 3 is permitted to rotate
only a distance corresponding to a series connection of the motors.
The operation of this controller and the relation of the several co-operating

page_text: parts and the circuits will be more readily understood by referring to Figures 12
and 14.
When the brushes 10 are in the respective positions indicated in Figure 2,
these positions being designated in Figures 12 and 14 as u, u¹, u² and u³, the
circuit is open. Assuming that the fingers m, m³, are respectively in contact with
the strips on the drum corresponding to positions s, s¹, that the brushes r, r',
are respectively in positions a, e, on the drum d, and that brushes c, c¹, are in
the positions z, z¹ on the drum d, if the brushes 10 be moved in the clockwise
direction to bring the same respectively into engagement with the first contact.
pieces 7 of the respective sets, the current will enter the controller from the
trolley or other current collecting device t, pass through all of the resistance R
and the motors M, M³, in series to ground. As the brushes 10 are moved step
by step in the direction mentioned the resistance R will be cut out section by
section until the brushes 10 are respectively in positions v, vl, 3 and v³, when all
of the resistance will be cut out of circuit and the motors will be in series, as
indicated in the second position Figure 13. As the brushes move from left to
right from positions v, 1, 2, 3, to positions u¹, u³, u³, u, the resistance will be
cut in, section by section, and in passing over the insulating segments at u¹, 2.
, u, the circuit will be interrupted. The length of the contact strips on the
drum d and the relation between the elements of the gearing between the two
switches are such that the fingers m, m¹ will pass on to the strips corresponding
to positions p, p, while the brushes are passing from points u¹, u³, u³, u, to the
first contact pieces 7 of the next succeeding sets, and when this point is reached,
the motors are connected in parallel with all of the resistance in circuit. This
resistance is then gradually cut out by the movement of the brushes 10 until
the points v, 1, 23, 3 are reached, when the motors will be in parallel without
A further rotation
resistance, as indicated in the third position in Figure 13.
of shaft 3 a sufficient distance will bring gear segment 20" (Figure 5) into mesh
with pinion segment 21, and thus quickly move drum d to bring fingers m and
m respectively into engagement with contact strips w and w¹ as well as the
corresponding wider strips, at the same time the resistance will be still cut
out of circuit. In this final position the coils and are connected in shunt
to the respective field-magnets f and f¹ of the motors M and M¹.
In order to reverse the current in the field magnet windings f and f¹ of the
motors, the drum will be turned to bring the brushes r r¹, respectively into
positions y and y¹. The connections may be obviously made so as to reverse the
current in the armatures a and a², if desired. In order to cut out the motor M
the drum will be turned to bring the brushes respectively into positions *
and 3, and to cut out motor M, the drum will be rotated to bring the
brushes c, respectively into positions, 25.
Referring now more particularly to the controller illustrated in Figure 3 and
Figures 6 to 11, the series parallel drum d is provided with a greater number of
contact strips for the reason that there are four motors and it is desired to
couple them in series, in series-parallel and in parallel, the series connection being
made when the brushes m are in contact with the strips corresponding to posi-
tions the series-parallel connection, when the brushes m and m¹ are respec-
tively in contact with the strips corresponding to the positions sp and s¹ pl; and
the parallel connection, when the brushes m and m₁ are respectively in contact
with the strips corresponding to positions and pl. the gearing between the
shaft 3 and the drum d being so proportioned that the change from series to
occur when the
series-parallel and from series-parallel to parallel will
circuit is broken by the resistance varying switch, i.c., when the brushes of said
switch are in positions u, u, u² and 3, as has been already described in substance
in connection with the two motor controllers.
In this controller, instead of employing a reversing switch at one side and a
cut out switch at the other, I employ two combined reversing and cut-out switches,

page_text: one at each side of the series parallel switch, and each comprising two drums ³
and d, normally fastened to a single shaft 39 by means of a suitable locking
device 40, but independently detachable therefrom in order to cut out any one
of the motors.
The gearing for the reversing switch at one side is substantially the same as
that heretofore described in connection with the controller for two motors and
comprises a segment 41 rigidly mounted upon the shaft 39 and a gear segment 42
meshing therewith and rigidly mounted upon the rod 43. This rod 43 also
carries or is provided with a head 44 having the usual three notches-45 with
which co-operate arms 46 and 47, coiled spring 48, and the locking lever 36.
The reversing switch drums at the other side of the controller are operated
simultaneously with those operated directly by the mechanism above described,
the means for effecting this simultaneous operation comprising an arm 49 rigid
on each shaft 39 and a connecting link or bar 50 between the said arms.
In order to cut out any one of the motors, I provide for each cut-out drum a
cam-shaped plate 51 having a notch 52, the cam plates for the drum being
located at the bottom and those for the drum at the top. Rigidly mounted
upon a shaft 53 at the rear of the right hand drum and d are elbow levers 54,
the outer end of which respectively rest against the cam surfaces of the corre-
sponding plates 51. Each is pivotally connected by means of an arm 55 to onc
end of a bar 56 and the latter is pivotally connected at its other end to an arm 57
rigid on a shaft 58 at the other side of the controller.
The shaft 58 is also provided with two elbow levers 54 to co-operate with the
When any
cam plate 51. The arm 36 is also rigidly connected to shaft 58.
one of the drums is unlocked from its shaft and turned from right to left, the
free end of the lever 36 will be raised into the groove 37b, thus preventing
movement of the shaft 3 beyond the position corresponding to a series connection
of the motors.
An auxiliary means for preventing operation of the controller beyond the position
corresponding to series connection of the motors comprises a shaft or rod 65 provided
with a notched head 64 and a crank pin 64", the latter being located beneath one
of the brushes 10 in Figure 3 and therefore not shewn in that figure (see
Figures 7 and 8). A two-armed lever 59--65 is loose upon shaft 58 and the free
end of arm 65 is provided with a roller that engages with the notches in head 64.
The free end of arm 59 has one end of a rod 60 pivoted to it. The free end of
this rod is provided with a guide 61 and is moved outward to engage a stop 62
(see Figure 7) on the movable member of the switch by the action of crank
pin 64 upon a bifurcated lever 66 that is rigidly connected to lever 59--65, this
action taking place when the shaft 63 is turned to bring the roller on arm 65
into the outer notch in head 64.
Referring particularly to Figures 14 and 15, when the drums are in such
position that the fingers and 1 are respectively in positions
and x, the
motors are connected for movement in one direction, and when these
brushes are respectively engaged in positions y andy, the motors
are connected for movement in the opposite direction. When any drum
is detached from its shaft and rotated to bring the brushes r and r respectively
into positions z and z¹, the motor corresponding to this drum is cut out of
circuit.
Except as otherwise hereinbefore specified, the operation of this form of
controller is the same as that of the form shewn in Figures 2, 4, 12 and 13.
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
I claim is:
1. A controller for electric motors in which the switch for varying the resistance
in circuit with the motors is separated from the switch for varying the con-
nections of the motors, the shafts of the two switches being connected by gearing

page_text: so constructed that the operation of the resistance switch rotates the shaft of the
other switch at different speeds at different periods of its movement, for the purpose
specified.
2. A controller in which is provided a switch for varying the resistance in
circuit, a second switch for varying the connections of the motors from series to
parallel and vice versa, a third switch for reversing the connections of the motors
when required, and cut-out switches for cutting either of the motors out of
circuit when desired, the second named switch being connected by gearing with
the resistance varying switch and through interlocking devices with the reversing
and the cut out switches, substantially as described.
3. A controller in which is provided, a resistance varying switch connected
by gearing with a switch for varying the connections of the motors, and combined
cut-out and reversing switches connected through interlocking mechanism with
the switch for varying the connections of the motors, substantially as described.
4. Controllers for electric motors constructed and operating substantially as
described.
1000
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.