Improvements in Systems of Control for Electric Motors and Railway Trains.
Year: 1898

page_text: Date claimed for Patent under Sect. 103 of Act,
being date of first Foreign Application 17th Mar., 1898
(in United States),
Improvements in Systems of Control for Electric Motors and
Railway Trains.
I, WILLIAM B. POTTER, of Schenectady, State of New York, United States of
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 ascer-
tained in and by the following statement:-
My invention relates to systems of control for electric motors, and is particularly
useful in connection with such as are used in railway trains in which a number
of individual propelling units employing one or more motors are so connected that
while each furnishes its share of energy for the propulsion of the train, all may be
controlled from a single point. In such systems I find it highly advantageous to
provide the motors upon each car of the train with a separate controlling device,
preferably of the series parallel type, though other arrangements may be used.
Since the simultaneous manual actuation of a number of different controllers thus
located is practically impossible, I have devised a simple system of control by
which all of the regulators or controllers upon the different cars may be simul-
taneously and synchronously actuated by power as, for example, by the electric
current which propels the train, and controlled from a selected point.
My invention, therefore, contemplates the use of a number of motor controllers,
or controlling devices, and one or more master controllers, each capable of control-
ling the action of a number of motor controllers. Such a system is chiefly
applicable to motor vehicles, and particularly when a number of such cars are
united to form a train, though it is also useful in other connections.
I find it essential that the connections between the master and motor
the step-
controllers should be more positive than is possible with
by-step devices used in connection with electric indicators and similar work. My
invention, therefore, aims to provide an arrangement whereby any movement of
the master controllers, of any magnitude in either direction, will be followed by
a corresponding movement of all of the motor controllers governed thereby.
Further, I aim to provide an arrangement by which the various changes in the
resistance and arrangement of the motor circuits take place at a rate of speed under

page_text: the control of the motor man, up to a certain point only, but, beyond that point,
automatically maintained at a certain fixed maximum, whereby the too sudden
starting of the motors is prevented. My invention also comprises a new and
improved arrangement for retarding and controlling the retardation of the car or
train, such that the braking effect, as well as the acceleration effect, of an entire
train of cars may be controlled by simple electro magnetic means, operated with a
single point.
My invention also includes certain improvements in telemotric control, and
various methods and combinations to be hereinafter more fully described and
claimed.
In each of the controlling devices it is preferable to provide definite points at
which the device will rest for such times as the motor mau may wish. may
accomplish this result by driving each of the motor controllers by a source of
power, controlled by the master controller, and providing a set of electrically-
controlled stops, acting to check each of the individual motor controllers at a
position defined by the position of the master controller.
For this purpose I prefer to employ a set of stops which may be withdrawn by
the action of the electric current. All of those of similar positions in the different
controllers are preferably connected in common circuit so that they are simul-
taneously actuated. As the stops are successively withdrawn the cylinder of each
controller advances under the action of the source of power above-mentioned, which
source of power is preferably a small electric motor mounted at or near each motor
controller, until finally the highest speed position of the controllers is reached.
For resisting the action of the motors, I provide suitable springs, which have
sufficient strength to rotate the controllers backward when the current is shut off
from the small motors. It is, of course, within my invention to do away with the
springs, by reversing devices of any kind, applied to the small motors. The spring,
however, has some advantages, amongst others, being the fact that if, for any
reason, the current fails, the controllers are all brought to the off position, in which
the train circuit is lead, this forming a useful safety device, and preventing an
accident on the sudden restoration of the current.
I have illustrated embodiments of my invention in the accompanying drawings,
in which Fig. 1 is an end elevation of the motor controlling device, which is prefer-
ably placed under each motor car. Fig. 2 is a detail, partly in section, of the parts
shown in Fig. 1; Fig. 3 is a diagrammatical side elevation of a train equipped
with my invention; Fig. 4 is a diagram of circuits, with a controlling device for
actuating all the motor controllers, and Fig. 5 is a diagram of all of the controller
circuits, by means of which the propelling motors of the train are driven, while
Figs. 6 and 7 are end views and Fig. 8 is a diagram of the circuits of a "brake"
controller system.
In Figs. 1 and 2, A is a plate forming at once a cover and a support for the
operating parts of the controller, and B is the governing motor, geared to the con-
troller shaft by the reducing gears C, D. The field magnet coils are shown at B¹,
and the armature at B. The governing motor is of any well-known form, and is
preferably series wound. E, E are the springs acting to restore the controller to
zero. With the ordinary rheostatic or series parallel controller, only one spring
need be used. Where, however, the controller is designed for operation in two
different directions, as is commonly the case in controlling devices in which electric-
brake circuits are embodied, the two springs may be wound in opposite directions,
and will then tend to restore the controller cylinder to zero or to the off position,
in which ever direction it is moved by the motor. These springs as already pointed
ont, are of sufficient strength not only to overcome the friction of the controller
contacts, but also to rotate the motor when the circuit is cut off.
Fis an arm upon the controller shaft, provided with two pawls F1, F2, the pawls
being controlled by springs F3, F3. The arm rests in the off position. against the
stop S, and a similar stop S is provided on the other side of the controller to limit
its movement in that direction,

page_text: It will be observed that the pawl F2 is free to move only to the right, or down-
ward, as shown in Fig. 1, and that the pawl F may move only in the opposite
direction. Projecting through the cover A are two sets of reciprocating pins,
lettered respectively G and G. Each pin G is connected to one of the pins G¹
by a lever or link G, bearing in a lug G, which projects from the cover A. Retract-
ing springs tend to keep the pins & below the path of the pawls F. Solenoids I
are provided which, when energized, act to withdraw the pins G from the path of
the pawl F, and at the same time to raise the pins G into the path of the pawl F¹.
It will be noted that on one side of the controller there are seven of these stops or
step-by-step devices, and on the other side five, while between the sets is a blank
space. A well-known form of series parallel controller is illustrated as the one
employed, the pins on one side representing the series positions with their resis-
tances, and those on the other side the multiple positions, while the blank space is
the transition point from series to multiple, upon which the controller is not sup-
posed to stand. In Fig. 2 will be seen another plate A', forming a cover for the
controller, and a bushing A² around the shaft K¹ of the controller cylinder K,
itself, of which only the upper portion is shown.
Fig. 3 shows a train in diagram, having a motor controller K and two master
controllers L, on each car, which is the preferred arrangement though not essential.
A cable is shown connecting the various pieces of apparatus. The system of
supply illustrated is the well-known third-rail system, and the contact-shoes T are
shown on the trucks of the train between the wheels.
Fig. 4 is a diagram of the circuit connections, showing one master controller and
two motor controllers wired to the cable M.
The main switch L of the master controller is shown as consisting of a number of
fixed contacts a, b, c, d, etc., over which sweeps a movable sector L. The sector
is driven by the arm L', through a lost motion device, and carries the contact i,
and the insulated brush k. The contact is connected to line through the shunt m
of the ammeter #.
The contacts to 4 inclusive of the master controllers are connected in multiple
to the wires composing the train cables M, and in circuit between these wires and
the ground wire L' are the solenoid coils I.
In the position shown in Fig. 4 current enters from the trolley or shoe T and,
passing through the resistance m and indicating by its proportionate reading on
the ammeter the flow of current, goes first to the contact a, and thus to the larger
sliding contact sector L2 on the controller L. The circuit is still open, however,
the contact being insulated from contact L³. If the arm L' is thrown in a right-
handed rotation until L3 touches k, current flows to the contact L and directly to
the small series motors B, B, and to ground. The arms F, of all the other con-
trollers are thus actuated until they touch the pins or studs G (as in Fig. 2) which
are projected through the case to stop them.
At the next step of the switch L the contact is put in circuit, and the first of
the pins G is withdrawn by its corresponding solenoid. As the motors B, B, are
still supplied with current, the controller arms are now brought against the second
of the pins G. As the first pin G is retracted, the corresponding pin G¹ is thrown
up, and acts to prevent the arms F, F, of the controllers, from being brought back
to the off position by any accident except one which would deprive the motor of
current. Corresponding actions take place as the contacts to are touched, until.
finally, the arms F are brought around against the stops S¹. It will be observed
that the pins G' offer no obstruction to the arm F, while it is rotating toward full
speed positions, because the pawl F¹ is free to pass them, and vice versa, the pins G
offer no obstruction to the pawl F as the controller returns to the off position.
The backward operation of the motor controller arms through any desired angle
is accomplished by moving the arm L' in a left handed rotation, until the sector Le
assumes the position corresponding to the desired position of the motor controllers.
The action is as follows: The contact L³ leaves the brush k, by virtue of the lost
motion connection, and the circuit of the motors B is at once opened, so that the

page_text: springs E (Fig. 2) tend to return the arms F to the off position. But such motion
is prevented by such of the stops Gas are elevated.
Therefore, the arms will return only to the position corresponding to the last one
of the brushes a, b, c, etc. in contact with the segment L².
It will then be seen that the motor controllers may be actuated in absolute
synchronism to any desired amount, and in either direction, by the action of a
single master controller. It is also obvious that any one of the master controllers L
shown in Fig. 3, may be used to accomplish the desired result.
To avoid unnecessary complications of the drawings, I have shown the motor and
master controllers in Fig. 4 arranged for a less number of positions than that in
Fig. 1, but it is evident that the number may be varied to suit any requirements.
The devices thus far described, are evidently sufficient for throwing the ordinary
series parallel controller to any of its positions, no matter how many points the
controller may have. But it is also necessary or useful, to throw a reversing switch
for determining the direction of motion of the cars, and one such reversing switch
is preferably attached to each motor controller, as will be more fully shown here-
after. Two of these switches are shown at P', in Fig. 4, one corresponding to each
of the motor controllers. Each reversing switch is shown as consisting of four
sets of contacts 1, 12, 13, 14, arranged on a cylinder, and capable of bearing, two
sets at a time, against brushes P³, 1. The position of each reversing switch is
controlled by two solenoids P, P. The circuit connections to these solenoids are
as follows: Starting from the shoe T, a wire passes to the master reversing
switch (2. This switch is provided with two contacts Q, Q, from which wires lead
respectively to the sets of solenoids P7, P8. With the switch Q in the position
shown, current will pass from the contact shoe through the solenoid P and to the
ground, and the reversing switches will be thrown to the position shown, which will
be assumed to be the position corresponding to the forward motion of the train.
With the switch Q on the contact Q, the solenoid P8 will be energized, and the
reversing switches will be thrown in the opposite direction.
In Fig. 5 I have shown a development of a suitable motor controller and its
connections. The controller operates on the well known series-parallel principle,
by a series of steps in which, as the combination passes from series
to parallel, one of the motors is shunted, its circuit then opened,
and, finally, it is connected in parallel with the other motor; resis-
tance being cut in or out to facilitate these changes. The par-
ticular controller illustrated brings in resistance sections in multiple, so that as
each section of resistance is cut in, the total resistance of the circuit is lowered.
The rotation of the controller is towards the right; the contacts 2 to 13 are station-
ary brushes of the usual type, while 1 is a trolley contact permanently connected to
the collector T, which is the collector already shown in Fig. 4. Contact 2, 2b, etc.,
to 8, are resistance steps acting to cut in, in multiple, the resistances R', R², and
thus to reduce the total resistance of the circuit. Contacts 9", 11", are the ordinary
series contacts 10 to 13 are the parallel contacts. Where the contacts 11ª, 1
overlap slightly, one motor is shunted. The circuit will be traced only through
the series position, inasmuch as the other combinations are self evident.
Starting from the shoe T, current passes to the trolley contact 1, and thence
through the various steps of resistance however that may happen to be in circuit,
to the lead connected to the brush 2, thence to the reversing switch RS, by con-
tacts 17 and 16 and 16", through the armature M³, by 15 and 14 and 14" through
the field M2 of the first motor, to contact 9, by cross connection to contact 11, thence
through the contact 18 to 21 of the reversing switch, and through the second
motor to ground.
It will be evident that with the brushes 14, 15, etc., of the reversing switch RS
bearing upon the left hand side of contacts, the motors will be connected to run
in the opposite direction. The change in the position of the reversing switch is
made by the switch Q, of the master controller, as above explained. This particu-
lar controlling device is illustrated simply as one adapted to the purposes of my

page_text: invention and which may be applied to systems of train control, such as I have
referred to.
My invention also comprises an arrangement by which the motors may be
accelerated, regulated and retarded from a single point, by use of the apparatus
thus far described in combination with some suitable electrically controlled or
actuated braking device.
For such work I prefer to use motor controllers arranged as shown in Fig. 6
or in Fig. 7. The device shown in Fig. 6 is similar to that shown in Fig. 1, except
in the arrangement of the stops G, G. The arm F, the stop S, the spring or
springs E, etc., are left as before, but the stops are arranged in three steps, corre-
sponding first to the brake positions, second to the series positions, and third, to
the multiple power positions. The arm F is shown in the off position, and tends
naturally to be returned against the stop $2 through the brake positions. With
such an arrangement, when the master controller switch L is first closed, the motor
controllers work through the brake positions to the off position, and finally to the
series position. They may be obviously be retained on the off position by properly
setting the switch L, and will remain there as long as current is supplied to the
motors. On any momentary interruption of the current, they will pass through the
brake position returning again to the off position when the current is restored.
The arrangement shown in Fig. 7 is identical in result but different in arrange-
ment. Two springs E and E2 are used, working in opposite directions, so
arranged that their combined action tends to bring the motor controller to the off
position, which is the position shown in the figure. The small motor which drives
the controller is provided with a reversing switch, under the control of the master
controller, as will be obvious to one skilled in the art, and is thus capable of
driving the motor controller either right-handedly, for power, or left-handedly,
for brake, by proper rotations of the switch L.
I have shown in Fig. Sa diagram of motor controller and motor circuits arranged
to be operated in connection with either one of the devices shown in Figs. 6 and 7.
In this figure m³, m³ are the armatures and m², m are the field magnets of the
motors, while s, are brake shoes, or other electrically controlled or operated
brakes, of any well known type. The main controller is shown at K, reversing
switch at RS, and the brake switch at BS. The brake switch is really part of
the controller K, and is preferably mounted on the same cylinder. Suppose the
brushes 14 to 21 of the reversing switch RS, bear upon the left hand rows of con-
The
tacts 14" to 21", and that the brushes 23 to 40 bear upon the line 1-1.
brushes 41 to 44 will then bear upon the line 11, 11. Current then enters at the
trolley or shoe T and passes to the brush 23, and thence to the contact 23", thence
by cross connections to the contact 28 to the brush 28, and thence through the
resistance R to the brush 34, contact 34", cross connection, contact 38, brush 38,
brush 14 of the reversing switch RS, brush 15, motor armature m', brush 16,
contact 16, brush 17, brush 36 of the switch K, contact 36", cross connection,
contact 37, brush 37, motor field me, brush 44, contact 44", cross connection, con-
tact 31, brush 31, brush 18 of reversing switch RS, contact 18, brush 19,
armature m³, brush 20, contact 21", brush 21, brush 35 on switch K, contact 35º,
cross connection, contact 39", brush 39, to field magnet m and to ground. This
obviously connects both motors in series with the resistance R.
It will be noticed that in this position the brush 43 bears on the contact 43,
which is cross connected to contact 29" so that a circuit exists from the shoe T
to 23, 23", 28, 28, and to the common point between the resistance R and R³, as
before, thence through R3, 43, 43", 29, 29, to the brakes s s', and to earth. This
serves to pass a demagnetizing current through the brake shoe where it is considered
necessary. These conditions are then as shown in diagram in Fig. 9.
Further rotation of the controller K acts to open this demagnetizing circuit, and
to cut out the resistance R. 4-1 is the full series position. In passing from 4---4
to 5-5, one motor is shunted, as explained in connection with Fig. 5, and 5-5
to 8-8 are the multiple positions. The various brake positions are indicated by

page_text: the lines 9, 10, 11, 12, 13 and 14. Suppose the brushes 23, etc. to rest upon the
line 9-9, the circuit may be traced as follows:
Referring to Figs. 8 and 10 and starting at the ground connection.
Through the brakes stands to brush 2, contact 29, cross connection, contact 27"
brush 41, resistance R, brush 34, to contact 34. Here the branch circuits begin,
one through 35 and one through 36. Tracing the latter of these first, the upper
one in Fig. 10 will pass to brush 36, brush 17, on reversing switch RS, brush 16,
through the armature of motor m³, to brush 15, brush 14, and brush 38, to con-
tact 38. The set of contacts 37° to 40° inclusive, are connected together by a
cross connection which forms the equalizer wire shown in Fig. 10.
Returning to the contact 34, the second branch circuit, the lower one in Fig. 10,
passes to 35b, brush 35, brush 21, on reversing switch RS, through the contact 21",
to brush 20, to the motor armature m³, to brushes 18 and 17 on RS, to brush 40,
and then to contact 40b, the equalizer.
the upper
Starting again at this equalizer, there are two branch circuits, one,
one in Fig. 10, by cross-connection to the contact 37b, the field m², to contact 32,
to segment 32, by cross connection to segment 33, to contact 33, and to ground.
The other circuit from the equalizer to ground leads by cross connection to 39",
to brush 39, through field m, direct to the ground wire.
The effect of rotating the controller to the positions 10, 11, etc., is to gradually
cut out the resistance interposed in the circuit of the braking generators and to add
to the retarding effect.
The connection of the various controllers in multiple between the source of
supply and ground enables me to employ cut-out switches CO (see Fig. 4), by
which any one of the controllers may be cut out without affecting the operation of
the others, so that, in the event of any accident to a motor or controller on one
car, that car may still be employed in the train as a trailer," the other car or cars
furnishing the necessary motor power.
It will be seen that by my improved system I am able to control a train of
cars for power and for brake, with the same facility and positiveness available in
the control of an ordinary single motor car. I procure an even acceleration and an
even braking effect without bumping, since each car is accelerated and retarded
with the same force as that applied to all the other cars. I also avoid the necessity
of placing air brakes upon the train, and render the whole control of the train, both
for power and braking, purely electrical or, at least, electrically controllable, and
therefore, capable of the most delicate and the most rapid action. I prefer to so
adjust the motors 13, which drive the motor controllers of the train, that when
current is freely admitted to them they will drive the controllers at the rate most
suitable for the desired acceleration without danger to the machines, which rate I
find to be such as to produce a constant current, not exceeding that at which the
wheels will slip, in all the motors of the train. Obviously, if it is desired to
accelerate the motors at less than maximum rate, the motor-man has simply to
turn the master controller slowly, so that a slow rotation of the master controller
will be followed by a slow rotation of the motor controllers, while a rapid rotation
of the master controller will be followed by a corresponding rapid rotation of the
motor controllers up to and not beyond that speed of rotation which experience
shows to be best for any particular installation.
Though I have particularly described my invention in connection with electric
train systems, it should be understood that it is applicable to other uses.
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 system of control for an electric railway, comprising a number of motor
cars, a controller upon each motor-car for the motors thereof, step-by-step actuat-
ing devices for each controller, and a common regulator on the train simultaneously
and synchronously controlling all of the step-by-step devices.

page_text: 2-A system of train control for an electric railway, comprising a number of
motor-cars, each of which is provided with a controller for its motor, the controllers
being in parallel between the source of supply and ground, step-by-step actuating
devices for each controller, a circuit or circuits including the step by step actuators,
and a regulator in the circuit or circuits governing the actuators.
3 In a system of train control for electric railways, a number of motor-cars
provided with controllers governing the motors of the respective cars and con-
nected in parallel between the source of supply and ground, a regulator upon the
train controlling all of the actuating devices simultaneously, and cut-outs for each
actuator arranged to cut-out any controller without affecting the operation of the
others.
4. In a train system, the combination with a number of cars provided with
separate controllers, of means controlled by said controllers for propelling said
cars, and for positively retarding the motion of said cars, and means for simul-
taneously operating all the said controllers from a selected point.
5 In a train system, the combination of a number of cars provided with
separate controllers, of means controlled by said controllers for propelling said
cars, and for positively retarding the motion of said cars without absorbing power
from line, and means for simultaneously operating all the said controllers from
a selected point.
6-In a train system, the combination with a plurality of motors or sets of
motors, of a plurality of controllers each adapted to connect and regulate one set
of motors for positively accelerating the train or for retarding it by acting as
braking generators, and means for simultaneously operating all the controllers
from a selected point.
In a train-control system, the combination with a plurality of sets of brakes
and motors, of a plurality of controllers, each adapted to regulate one set of brakes
and motors, and means for simultaneously controlling the operation of all the con-
trollers from a selected point.
8-In a train-control system, the combination of a plurality of brakes and motors,
or sets of brakes and motors, of a plurality of controllers, each adapted to regulate
one set of motors for power and braking purposes, and also to apply one set of
brakes, and means for simultaneously operating all the controllers from a selected
point.
9 In an electric train system, the combination of a number of motor cars, each
provided with means for converting its motors into generators for braking the
train, the motor circuits of one car being independent of those of the adjacent car,
and means situated at a selected point for controlling the action of all the braking
generators.
10 The combination in a train system of a plurality of motor controllers each
comprising a switch arranged to supply current to a plurality of motors, or to assist
in retarding the train, and a reversing switch, and means for controlling all of
the said controllers from a distance.
11-In a train system, the combination of a plurality of motor cars. equipped
with motors and controllers, of stops for limiting the movements of the controllers,
and electro-magnetic means for controlling the stops of a plurality of controllers
from a single point.
12 In a train system, a plurality of motor cars, each equipped with motors, a
series parallel motor controller and a master controller, in combination with means
for driving the motor controllers in either direction, stops for limiting their move-
ment, and means whereby any one of the master controllers governs the stops of
all of the motor controllers.
18 In a train system, a plurality of motor cars each equipped with motors, a
series parallel motor controller, a contact device and a master controller in com-
bination with means for driving the motor controllers in either direction, stops for
limiting their movement, and means whereby any one of the master controllers
governs the stops of all of the motor controllers,

page_text: 14 In a train system, a plurality of controllers operated or controlled from a
common point, and means for operatively disconnecting one or more of said con-
trollers, or the operating means thereof, at will.
15 The combination with one or more motors, of a motor controller thereof,
electromagnetic means for operating said controller to cause, in proper succession,
various motor and resistance combinations, and a mechanism for returning the
controller to an initial point.
16 The combination of an electric train system, of a number of controllers
mounted on different cars, each adapted to connect the apparatus on one of the
cars for accelerating or retarding, and electromagnetic means for controlling the
operation of the said controllers from a distant point.
17 The combination with an electric car provided with a plurality of motors,
of a controller adapted to connect the motors in series or in parallel, and adapted
to retard the car by electromagnetic means, with electromagnetic means con-
trollable from either one of a plurality of separate points, for actuating the con-
troller.
18 In a system of train control, a plurality of motor cars provided with motors
and motor controllers, in combination with one or more master controllers, the
arrangement being such that a movement of the master controller in either the
on or "off" direction, through any number of steps, causes a corresponding
movement of all of the motor controllers.
<
23
19 The combination with an electric car and its motors of a controller adapted
to connect the motors for acceleration by its rotation in one direction and to cause
the retardation of the car, by its rotation in another direction, a spring or springs
arranged to return the controller to a selected point, and electromagnetic means
for moving the controller away from the said selected point.
20 The combination with a shaft, of means for actuating it in either direction,
a set of stops for preventing movement in one direction, and a set of stops for
preventing movement in the other direction, and means for withdrawing said
stops.
21 The combination with a shaft, of means for actuating it in either direction,
a plurality of stops arranged in pairs, one stop of each pair being so arranged as
to be in while the other is out, and means for actuating said stops.
22 The combination with a shaft, of means for actuating it in either direction,
stops arranged in pairs and so connected that while one stop is in, the other stop
is out, and a solenoid acting against a spring for controlling the motion of the
stops.
23 The combination with a shaft, of means for actuating the same, two sets
of stops, and two catches each arranged to pass freely by its respective set of stops
while moving in one direction, and not while moving in the other direction.
24 The combination with a motor controller, of a motor for driving the same,
a master controller for admitting current to the driving motor, and a lost-motion
connection in the master controller, such that a slight motion of the master con-
troller arm in either direction causes a corresponding motion of the motor con-
troller.
25 The combination with a motor controller, of a motor for driving the same,
and a master controller arranged to admit current to the motor by any movement
in one direction, and to cut off current from the motor by any movement in the
other direction.
Datad his 101.
1000