Improvements in Systems of Electric Train Control.
Year: 1899

page_text: Date of Application, 22nd Dec., 1899-Accepted, 14th Apr., 1900
COMPLETE SPECIFICATION.
Improvements in Systems of Electric Train Control.
We, THE BRITISH THOMSON-HOUSTON COMPANY, LIMITED, of 83, Cannon
Street, in the City of London, Electrical Engineers, do hereby declare the nature
of this invention (which has been communicated to us from abroad by William B.
Potter, residing at Schenectady, in the County of Schenectady, State of New York,
United States of America, Electrical Engineer), and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
:
This invention relates to systems for controlling the several cars of an
electrically-propelled train, the object being to provide the cars with independent
electric motors and to regulate the speed, torque and direction of rotation of the
motors from a single point in the train, so that the train may be composed of any
number of units controllable and regulable by a single controller.
The invention is particularly applicable to inter-urban or elevated railway
traffic, where a plurality of cars are used in each train, the simplification of the
controlling system, the minimizing of the number of parts, and the mounting
of the current-toning resistances for all of the cars on a single car, greatly
cheapening the cost of installation.
This invention is applicable to electrically-propelled cars of any type, whether
direct or alternating current, and single or polyphase in character. The inven-
tion however is especially applicable to cars propelled by alternating current
motors of the polyphase induction type.
In carrying out the invention each car is provided with one or more propelling
motors, suitable feed wires being carried through the train and terminating at
the ends of each car in connecting devices by which a common supply system
may be provided for the entire train. Current is led from the source of supply
by a suitable collector or collectors which lead to the controller in a pilot car,
by which is meant the car upon which the common controller for the system is
located. On this car is mounted also a series of resistances for graduating the
strength of current in the several armature circuits of the motors of the train,
and thereby graduating the torque and speed of the motors. A considerable
number of independent resistances are mounted on the pilot-car, as many as the
requirements of train service will call for as to the maximum number of cars
per train.
The controller is organized to render all or any desired number of
these resistances operative, according to the number of cars in the train. If a
polyphase system of the two or three phase type be employed, we use two supply
wires, from which the current is collected by trolleys or other suitable devices,
and provide two independent conductors extending throughout the train; the
several motors connect in multiple with these conductors, ground connections

page_text: from the several motors being utilized as a third conductor or common return.
The amount of resistance necessary to provide for the increased flow of current
with an increased number of ears is graduated by switches on the pilot-car.
This invention therefore comprises a system of train control having a plurality
of cars the speed and torque of which is governable by a single controller and
rheostat mounted at some point of the train. It comprises further such an
organization in which the current-carrying capacity of the rheostat is variable
to permit control of trains of different sizes. More specifically it comprises an
alternating-current system of train control, in which the several cars are provided
with induction motors connected in parallel to leads extending throughout the
train and governable as to speed and torque from a single controlling point.
Other features of novelty will be hereinafter more fully set forth and definitely
claimed.
In the drawings, which illustrate the invention, Fig. 1 is an elevation of a
railway train showing three cars, the number being selected simply for the purpose
of convenience in the drawing. Fig. 2 is a diagram of the system of current
control and distribution in a polyphase alternating-current system supplying a
train driven by induction motors. Fig. 3 shows a modification of the current-
collectors on the pilot-car.
We have shown in the drawings a train of three cars. An important point
of our invention is that we permit a variable number of cars to compose a train,
the maximum number being limited only by the capacity of the controller on
the pilot-car. This controller is shown diagrammatically at B in the drawing,
the disposition of the several contacts representing a development of the controlier
cylinder. As exemplified in the drawing, there are twenty three pairs of con-
tacts, marked respectively 1 to 23 and 1 to 23ª. The first four contacts are
devoted to the reversing-switch shown at 1b, 3b, which may be constructed in the
usual manner, two of the contacts leading to supply wires, if a polyphase system
be employed, and the others leading to the controller. Extending through the
train are two pairs of conductors or leads a, b and c, d, the former of which
connect with two of the rotary field leads of each motor, coupling the several
motor field-magnets, in parallel relation, as shown, and the latter connecting with
two ring contacts on the several armatures or secondary motor members, coupling
them in a similar relationship. The third terminal of each field-magnet and
armature winding of the motors is grounded as indicated. The leads a, b which
supply the field magnet winding of the primary members of the induction
motors, connect with two contacts 5 and 8 of the reversing switch, thereby
providing for a reversal in the direction of rotation of the rotary magnetic field
and consequently a reversal of the motors. The armature leads c, d connect
with two controller contacts, as 10 and 15, a third contact, 20, being connected
with the ground. A plurality of resistances, as indicated at R', are connected
in parallel through controlling hand switches S. In the system shown in the
drawings there are three sets of these resistances R1, R2, R3, one for each phase of
the system; for a polyphase system but two would be necessary. If a system
of a higher order were employed, more would be necessary. As many of the
individual resistances ¹, a, as there are cars in the train are cut into each
circuit, three being shown thus connected. There are three groups of contacts
in the controller, one group for each resistance, co-operating with corresponding
movable contacts arranged first to close the circuits on three resistance sections
coupled in parallel, then to halve the resistance, then to put the motor on short-
circuit. This result is accomplished in the usual manner by making some of the
movable contacts shorter than the others, as exemplified in the diagram.
The method of controlling the train will now be understood. The reversing
switch closes the primary or field magnet circuit over a path from the collector T,
and, say, contact 1b, contact 2, contacts 6, 6ª, 52, 5, through one of the field-magnet
windings to the neutral point, a star winding being shown,-where it branches,

page_text: one branch passing to ground through a second field magnet coil and the other
through a third field-magnet coil to contact 8, thence by 8, 7, 7, 3, 3 and 4 to
the companion collector T3. The field-magnet contacts 5, 6, 7 and 8 are somewhat
longer than the armature controlling contacts, as shown, in order to provide
for a rupture of the field-magnet circuit after the armature circuit has been
opened, to subdue sparking. In operating the controller, the armature circuit
is closed by way of conductor c¹ to contact 15, contact 15, where it divides, one
branch passing by 14ª, 14, 13, through the three resistance sections R' in multiple
to contact 11, to contact 11ª, by contact 10 to 10, thence by conductor d to the
several armatures, and the other branch passing to contact 16, 16, through three
resistance sections of group R2, contact 18, 19, 19, 20, 20, to ground, thence to
the ground of the several motors. A third branch passes by conductor d',
contact 10, thence to 10ª, 9ª, 9, 23, resistance sections of R³, contact 21, 21ª, 20",
to ground.
A second step in the manipulation of the controller brings the group of con-
tacts 12, 17 and 22ª into engagement with corresponding fixed controller studs
or contacts, thus cutting in an additional set of resistance sections for each
current phase and permitting an increased flow of current and greater torque in
the motor, and also preventing overheating in the resistances due to such increased
flow of current by reason of the increase of carrying capacity. A third set of
contacts 13ª, 18 and 23 places the several coils of the armature on short-circuit,
thus giving the maximum speed to the several motors.
It will of course be understood that more than three steps in the graduation of
the speed may be provided if desired. Thus, it will be seen that all of the
motors of the train connect in parallel, and have their torque and speed graduated
simultaneously by the operation of a single controller.
In order to permit any particular car to be. disconnected from the supply
circuit we may provide a four point switch for each motor, as indicated at F, F,
Ly which the field magnet and armature circuit may be simultaneously opened.
Thus, in case of accident to a motor or other emergency, the cars may be indi-
vidually controlled. In single track systems it will be found desirable to provide
the pilot car with an auxiliary current reverser, as shown in dotted lines at G,
which it will be necessary to throw when the pilot-car changes its position end
for end in order to preserve the same relationship of the motor or motors on the
pilot-car to the several motors of the train. Even where the pilot-car is not
provided with motors, such an auxiliary switch will be found desirable to preserve
uniformity in the direction of motion of the operating handle, and prevent
mistakes, which in cases of emergency might prove disastrous. The same result
might be accomplished in a system where the supply conductors are located at
one side of the track, by providing the pilot-car with collecting devices on each
side, as indicated in Fig. 3. Obviously in such an organization the same collector
will engage the same supply wire irrespective of the position of the car, and
the auxiliary reversing switch will not be necessary. It will of course be under-
stood that in operating the reversing switch the change of connections in two
of the motor leads will be sufficient to reverse the direction of the rotary field.
Thus but four train wires are needed to control the motors. In case of the
addition of more cars to the train, some of the hand controlled switches st, s2, s,
one for each car added, should be connected to the corresponding resistance
sections.
Having now particularly described and ascertained the nature of our said
invention (as communicated to us from abroad) and in what manner the same is
to be performed, we declare that what we claim is:-
1-A controller system for electric railway trains, comprising a plurality of
motors mounted on the several cars, and connected in parallel with a common
source of supply, and a controller mounted at a single point in the train for

page_text: graduating the strength of current proportionately to the number of cars in the
train.
2-A controller system for electric railway trains, comprising a plurality of
motors mounted on independent cars and connected in parallel relation with
supply conductor extending through the train, a controller mounted at a single
point in the train, and means operated thereby for graduating the flow of current
proportionately to the number of cars in the train.
3-A controller system for electric railway trains, comprising a plurality of
motors mounted on independent cars and connected in parallel relation with supply
conductors extending through the train, a controller mounted at a single point
in the train, and a variable resistance regulable to permit trains of varying
numbers of cars to be supplied through the same controller.
4-A controller system for electric railway trains, comprising a plurality of
motors supplied by a common train circuit, and a controller mounted on one car
of the train, said controller being provided with two current-reversers in series
relation to one another, for the purpose described.
5 In an electrically operated railway train, a plurality of motor-driven cars
controlled from a single car of the train, and means for reversing the current in
the motors relatively to the controllers to provide for a change of position of
the controller car end for end.
6-The combination in an electric railway, of a number of polyphase alter-
nating-current motors installed upon different cars of a train, with controllers for
all of the motors, located at one point upon the train.
7-In a polyphase electric railway, the combination of a number of cars each
equipped with one or more polyphase motors, and a switch at a desired point on
the train for regulating the resistance of the secondary circuits of all of the
motors.
8 In an electric railway, the combination of a number of cars, each having a
pair of polyphase motors upon it, with a controlling device at a desired point
upon the train, arranged to first connect the primaries of all of the motors in
multiple with a source of supply and afterwards vary the resistance of the
secondary circuits to regulate the speed and torque of the motors.
9-In a three-phase electric railway, a pair of metallic conductors, a ground
return, and a number of cars carrying suitable travelling contacts and polyphase
motors; in combination with a controller located at a desired point upon the
train, designed to first connect in the primary members of all of the motors
and then to change in a desired manner the resistance of the secondary circuits,
so as to progressively vary the speed and torque of the motors.
10 A controlling system for electric railway trains, comprising a plurality of
induction motors for driving the train, distributed among the several cars thereof,
a single controller for the train mounted at one point therein, and resistance
devices for the several current phases operated by the controller.
11 A controlling system for electric railway trains, comprising a plurality
of induction motors distributed throughout the train connected in parallel with
current leads extending throughout the train, a controller common to all the
motors mounted at a single point in the train, and independent devices operated
by said controller for closing the field magnet and armature circuits in the order
stated.
12 A controller system for electric railway trains, comprising a plurality of
polyphase motors distributed throughout the train, independent field magnet
and armature leads with which said motors connect in parallel relation, a plurality
of resistances governed by the controller in an armature circuit common to the
several current phases and means for varying the resistance according to the
number of cars in the train.
13 A system of control for electric railway trains comprising a plurality of
polyphase induction motors distributed throughout the train, the field-magnet

page_text: and armature windings of the respective motors connecting in parallel with two
pairs of train leads and ground, and a controller located at a single point in
the train, governing the motors.
Dated this 10th day of Dreamb 1900
THE BRITISH THOMSON-HOUSTON CO., LTD.,
ALFRED CLEMENTS,
Assistant Secretary.
J. J. MANHEIM,
T. R. THOMPSON,
Directors.