Improvements in Systems of Control for Electrically Propelled Vehicles and Trains.
Year: 1899

page_text: Date of Application, 30th Oct., 1899-Accepted, 20th Oct., 1900
COMPLETE SPECIFICATION,
Improvements in Systems of Control for Electrically Propelled
Vehicles and Trains.
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 and Frank E. Case, of Schenectady, in the County of Schenectady,
State of New York, United States of America, Electrical Engineers), and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
"
Our invention relates particularly to the control of electric railway vehicles
and trains and has for one of its objects to provide an efficient brake actuated
by electric current. Various forms of apparatus have been devised applicable
to the control of trains propelled by electric motors, each of the cars of which
is furnished with its own controller and motors, all of the controllers being
arranged to be operated by one or more master controllers," so called, situated
at different points, from any one of which it is possible to operate the train.
The advantages of this arrangement are apparent, as each of the cars may for
the time be the head of the train, no matter of how many cars it may be made
up, may be run backwards or shifted in one direction or another (as in switching),
with facility, from any one of a number of different points.
It is especially to this particular class of apparatus that our invention relates;
it aims to provide for such apparatus a convenient form of braking in which
the ordinary brake rigging of the car will be used, and be operated by a rotary
electric motor of sufficient power. As a convenient form of detent for this
motor, acting to stop its rotation wherever desired, we employ a magnetic
clutch. The general type of controlling apparatus herein illustrated as a con-
venient embodiment of the invention has separate electro-magnetically operated
contacts for the motor current, each of these contacts being controlled by its
own solenoid, and the current being admitted or shut off by the master con-
troller. To provide against those occasions when the trolley current fails, we
employ a storage battery with resistances arranged so that the full line potential
is not necessary, thus permitting the use of a battery of limited size. A reversing
switch is also provided, and this also is electrically operated under the control
of the master controller.
To operate the devices just briefly described, we have devised a controlling
switch or master controller, presenting several features of novelty. It com-
prises, in brief, a motor regulating switch, a brake switch, a switch by which
the magnetic clutch is controlled, and a reversing switch. These switches are
provided with separate operating means, and we have interlocking devices so
arranged that improper manipulation is rendered impossible. It is not enough
in this case to provide interlocks by which only one of the switches can be
operated at any one time; this has become a common feature in the art of
making controlling switches; but in our invention there are times when more
than one of the switches must be operated at the same time, for instance, when

page_text: the brake motor is applied there are steps in its application or points when
the motor has become stationary and at which it is desired to hold it. Under
these conditions, we have arranged to apply the magnetic clutch so as to hold
the braking motor. Other features of the interlocking device will be apparent
from the description and drawings.
Our invention comprises other features of novelty to be hereinafter pointed
out and claimed.
The drawings show a system in which our invention has been embodied.
Fig. 1 is a diagram of the circuits. Figs. 2 and 3 show respectively in side
elevation and plan a train equipped with the apparatus of our invention and
a single car-truck having the apparatus applied thereto; Fig. 4 is a front eleva-
tion, with the cover removed of the switches in the controlling device; Fig.
is a plan partly in section on the line 5-5 of Fig. 4 and, with the cover removed,
of the interlock, Figs. 6 and 7 are details in plan section on the line 6-6
and 77 of Fig. 4.
In Fig. 1 we have shown the circuits as applied to a magnetically operated
controller having separate contacts. In this figure the motor controller is shown
at P, with separately actuated contacts lettered respectively from pl to p; the
contacts of the master controller are shown in the upper part of the figure;
those designed for regulating the car motors are shown at K; embracing the
reversing switch, the switch for controlling the magnetic clutch and the brake
switch, are lettered respectively RS, MS and BS. These last three switches are
preferably mounted on the same shaft, though arranged to be separately operated.
The magnetic clutch is lettered MC, and the braking motor M. As will be
seen this motor is of the rotary type, and is geared to the drum D, upon which
the brake chain is to be wound as the motor revolves. The trolley T is shown
as a collecting shoe, appropriate for the now well known third-rail railways. A
circuit breaker CB is shown in the trolley lead, and a storage battery SB is
also illustrated. Resistances R₁ to R are provided to cut down the potential
between the trolley, the storage battery and the master controller. The arrange-
ment of these is such that current is delivered from the trolley lead to the
storage battery, through the resistance R'; it will be observed that bringing
the master controller to the off position does not interrupt this circuit. The
master controller operates the contacts p¹, etc., through the solenoid coils g₁ etc.,
and the currents in these coils is, as will be seen, at reduced potential, the
current flow being either from the storage battery through the lead a or from
the trolley through the resistance R2 to R and the lead b. In this case the
storage battery acts to equalize the potential across the solenoids, so that whether
many or few of them be in circuit, the potential will be practically the same.
The motor reversing switch RS is also included in the controller 1. As already
pointed out, this is electro-magnetically operated by means of coils C, C². A
brake B, acting upon brake wheel B' holds the switch in whichever position it
may be thrown by the current after the latter is turned off.
When
A description of the first circuit established by the motor controller K will
be sufficient for the purpose of this application to render clear the operation
of this device. Current enters at the trolley T, and passes through circuit
breaker CB, the resistances R2 to R4 lead b, contact 12, plate 12ª, contact 13,
plate 13, and thence to the contact upon the master controller K.
these contacts are brought to the first position of the controller, in
which they touch the rectangular contacts, (the latter being the develope-
ment in plane of the ordinary cylindrical switch), contacts 1, 2, 10, 12
and 13, are brought into circuit. It will be seen that the lead from contact 1
passes to the first four solenoid coils q to q and closes contacts p³ to p*. The
lead from contact 2 closes the circuit through the contact p in the same way,
thus throwing in the first section of the resistance R. The lead from contact 10
closes contact 14. Though the battery SB is normally connected to line
through the resistance R¹, yet when the master controller K is placed in an

page_text: operative position the contacts 12, 13, touch the plates 12ª, 13 and act to throw
in the resistances R2, R3, R in multiple with the resistance R. This serves to
reduce the resistance in series between the battery and the line whenever it is
called upon to give out current, and allows some current to flow from the trolley T
through the multiple bank of resistances to the coils of the separately actuated
contacts and thence to ground, thus reducing the amount of storage battery
capacity required.
The path of the motor current, with the connections thus established by the
first position of the master controller, is as follows: From the trolley T through
the circuit breaker, then through the contacts p', p, p, p which, as will be
seen, are arranged in two series banks, of two each in multiple, through the
contact p to the first section of the resistance R, whence it passes to the right,
to the contact 31 upon the reversing switch RS', then to contact 32, through
the armature A', back to the reversing switch at contacts 33 and 34, through
the field F, then across contact of the controller P, to contacts 37 and 38
upon the reversing switch, through the armature A2, then through the contacts 39
and 40, through the field F, to ground. As the master controller K is moved
so that the other developed contacts touch the fixed contacts 3 to 8, the other
resistance contacts of the controller P, lettered 6 to 70 are closed, and more
resistance coils are cut in, in multiple, and finally, contacts 1, 2 short circuit
the resistances. Part of these resistance contacts are then opened as the stationary
contacts 5, 6, 7 and 8 pass off the moving plates of the controller, to increase the
resistance of the motor circuit. At this point the contacts 10 and 11 respec-
tively touch plates 10 and 11, so that contacts p are simultaneously
closed. This has the effect of connecting the terminal of field F both to the
plus terminal of the armature A2 through the contact p", and contacts 37,38
of the reversing switch RS, and at the same time connecting the field to ground
through contact p thus throwing a shunt around the second motor. When the
contact 10 passes off plate 10 this shunt is opened, and when the contact 9
touches the plate 9ª the two motors M1 and M2 are thrown in multiple; the
first of these actions taking place when the contact is opened, and the second
when the contact 13 is closed, this furnishes a direct path for current
contacts 37 and 38 of the reversing switch RS, through the armature A2, and
through the field F2, by the contacts 39 and 40 on the same switch. This method
of passing from series to parallel by shunting one motor after cutting in resis-
tance enough to protect the apparatus, is well known in the art.
to
the
The motor reversing switch R S is operated by master reversing switch shown
developed in plane on the right, and marked RS. When these contacts are in
the illustrated position, the switch has already been operated and the contacts 29
and 30 are soon to be open circuited. If the switch be thrown so that 14b and 16b
touch the contacts 14 and 16, the path of the current is as follows; From the
trolley through the circuit breaker and the resistance R', or from the storage
battery SB to the contact 14, to 14b and to 16b then to the contact 36 upon the
reversing switch RS, by the cross connection to contact 35, through
the coil C, through the coil B2 to ground. The effect of this, as
coil C draws in its core, will be to rotate the switch RS¹ around the shaft æ;
at the same time the armature of the coil B2 will be attracted, withdrawing the
brake B from the brake wheel B'. The rotation of the switch will cause
contacts 35 and 36ª to pass from under the fingers 35, 36, open circuiting the
leads of the coil C¹. The coil 12 will also be de-energized and the brake B
will be applied, thus holding the reversing switch until switch RS is again
thrown to its illustrated position, when a similar action will take place, involving
the contacts 29 and 30, which are then in the same relation with respect to
plates 29 and 30³, that contacts 35 and 36 are in relation to 35 and 36*, in
the illustrated position of the reversing switch R S¹.
The magnetic clutch MC is controlled by the motor switch MS, In the
illustrated position the clutch is then open circuited, and therefore has no effect

page_text: on the brake motor shaft, but if contacts 18b, 19b of the switch MS be brought
into operative relation with contacts 18 and 19, current will be sent through the
clutch, and in this relation it will hold the motor in whatever position it may
happen to be. As shown, the operation of the switch MS acts to open circuit
the switch BS, so that if the clutch be applied, the motor M will have no
tendency to rotate while the current is cut off.
The motor M is operated from the switch BS. The path of the current through
this switch is from the trolley T to contact 18 of the clutch switch MS, to contact 17,
and then to contacts 20 and 21. These contacts are in multiple and co-operate
with the contacts 20ª, 21", etc. The upper row of these is arranged to occupy
a different relation to the lower in going off and coming on. it is desirable
that the connections to brake the motor be uninterrupted in applying the brake,
so that the torque will progressively increase and the brakes be applied with
greater and greater energy as the brake switch is rotated from its off position
to the final position in which all the sections of the resistance R are cut out.
We therefore so arrange the contacts 20", etc., (as will be further described
when explaining the mechanical embodiment of the invention), that in going
on they occupy a dotted line position as shown in Fig. 1, while in coming off
the contacts are both in the position shown in full lines, and thus the circuit
of the motor will be interrupted periodically. Current passes from these contacts
to contact 22, thence through the resistance 1, sections of which are progres-
sively cut out, until the motor is connected directly between the trolley and
ground.
These two lower contacts 27, 28, upon the brake switch BS, are for the purpose
of cutting in the resistance R2, R3, R, in multiple with the resistance R, and
act just as do the contacts 12, 13, of the switch K. It will thus be seen that
even when the trolley current is, for any cause, interrupted, the controller may
be operated, and the brakes may be set or released by current from the storage
battery.
Further, this arrangement makes it possible to use magnet coils and a brake
motor wound for, say, 100 volts upon a 500 volt circuit." It is highly difficult
in practice to build a very small motor or a magnet coil which will operate well
upon a 500 volt circuit. The arrangement shown further prevents the storage
battery, which is in general of small capacity, from being short circuited by the
car motors when the trolley circuit fails.
In Fig. 2 we illustrate a train of three cars N,N, N, with braking motors M, M,
controllers 1', and the master controllers A, in conventional diagram. Fig. 3
shows the same, parts but of one car only. It will be seen that the cable K¹
extends through the train, and is connected to all of the master and motor con-
trollers. The result is that all of the motor controllers of the train may be
energized from any one of the master controllers.
In Figs. 4 and 5, we show the mechanical structure of the master controller. The
reference letters in Fig. 4 correspond to those employed in describing the
circuits of the apparatus. RS is the part of the master controller controlling
the reversing switch, MS the part controlling the magnetic clutch, and BS the
brake switch. K is the motor controlling switch. 13 M shows the coil of the
blow out magnet, the other parts being removed. None of the fixed contacts
are shown, as they are sufficiently indicated in the diagram of the circuits.
The means of operating each of the switches just described is as follows:
The motor controlling switch Kis mounted on the shaft S3, and is operated in
the usual manner by its own separate handle. The reversing switch RS,
although mounted on the shaft S¹, is operated by a handle fixed to the shaft S
by means of an arm H2 rotating with the latter shaft, an arm H fixed to the
Eleeve carrying the switch RS, and a connecting link H¹. The switch MS of
the magnetic clutch is operated by the handle $4 fixed to the shaft S, upon the
right side of the controller, through an arm I fixed to the shaft, and another
arm I fixed to the sleeve of the switch MS. This construction is best scen

page_text: in Figs. 4 and 7. A spring I is provided, by which the switch is brought
readily to its off position, this action being assisted by the spring G shown
in Figs. 4 and 5, and presently to be described. The brake switch BS is fixed
to the shaft S¹, and is operated by its own independent handle fixed to the same
shaft.
The interlocking arrangements between these several switches are best seen
in Figs. 4 and 5. Referring to these figures, E is the star wheel or ratchet of
the controller K; E is a cam rotating with the shaft S2 of the reversing switch
handle, and E2 is a star wheel fixed on the shaft S¹. The two star wheels act
as step by step devices of well known character, for the motor controlling
switch and the brake switch. With the wheel E co-operates a pawl F having
the usual cam roller. A similar pawl F5 co-operates with the. cam E', and Fi
with the wheel E2. Springs G1, G2, G fixed to pins ggg, hold these pawls
in engagement with the star wheels. The pins are shown in section to indicate
that they are fixed to the cover of the controller, which is not illustrated. Upon
the shaft S, actuating the switch of the magnetic clutch, is a dog against
which bears the spring G, already referred to. Another dog F2 in the illus-
trated position prevents the operation of the dog F. A link F is fixed at one
end to the dog F; the other end is slotted at fand in the slot is a pin f fixed
to the pawl F¹. A spring G keeps the pin f in the end of the slot and
normally holds the dog in the illustrated position. In the cam are provided
notches el to et. When the circular portion of the cam surface between these
notches is opposite the pins f, f of the pawls F,F, these latter cannot be moved
from the notches in the star wheels E2, E, thus locking the star wheels in
position so long as the reversing switch with its cam E is in the intermediate
position, in which the contacts are broken. When this switch is thrown for
instance, so that the roller of the pawl is in the notch e, the notch e¹ permits
the pin f to enter as the star wheel E is rotated. The notch e in the wheel E
is so deep as to allow the reversing switch to be operated when the motor switch
is in the position shown, but the other notches in the wheel E are so shallow
that the pin f is not withdrawn entirely from the notch el except when the
switch Kis in its off position. A similar arrangement is found in the plate E²,
so that the reversing switch is locked until the other switches are turned off.
At the same time, the pin f³ is free to enter the notch e³, so that the brake
switch may be applied whenever the reversing switch is in either the forward
or back position. Set screws f, f', are arranged upon the backs of the pawls F, F,
so that when one of these is in its dotted line position, the other cannot be so
moved as to permit its switch to turn.
In bringing the train to a stop, it is desirable to hold the braking motor at
whatever point it may be set; this we accomplish by the magnetic clutch. The
manipulation of this switch at the proper time is of course of importance, .as
the braking motor could not revolve if. the clutch were set. This is provided
for by the dogs 12, 13. After the brake switch has been partially revolved, so
that the pawl F is in the dotted line position, the link draws the dog F2 to
its dotted line position, after which the switch MS may be turned, bringing
the dog to the dotted line position and holding it there by the toe f³. The
bevelled portion fe of the dog f² permits the dog F to push against the link F,
the slot permitting the latter to slide over the pin f, while the spring G
retracts the link and the dog F2 so that it engages with the toe f. When the
brake switch is manipulated, so that the roller of the pawl is brought up to
the circular portion of the wheel E³, the pin f pulls upon the link F and
releases the dog F, the spring G co-operating with the spring 12 (see Fig. 7),
to throw the magnetic clutch switch MS to the position in which the clutch
is released. This action being automatic, it is impossible for the motor man to
apply the brake without at once releasing the clutch and thus no harm can be
done to the braking motor.
In Fig. 6 we show a plan view of the arrangement indicated in Fig. 1, by

page_text: which some of the contacts of the brake switch are shifted. The upper set of
contacts 20 etc., of the switch BS is here illustrated. The wheel 3, which
carries these contacts, is provided with a slot Ein which plays a pin E, con-
nected to the next lower row of contacts. The contact wheel E is sleeved upon
the sleeve carrying the switch BS, so that, as the switch rotates, the pin E+
is first brought to one end or the other of the slot E, after which the wheel E
rotates in unison with the rest of the switch.
As already pointed out, when going on, the contacts E are in the dotted
line position, so that the multiple contacts 20 and 21, of Fig. 1, continuously
supply current to the switch BS; but when the switch is being retracted, the
pin occupies the position illustrated in Fig. 6, and the contacts 20" are in
line with the contacts 21", so that the supply of current is broken at each step
of the switch. Notches (1, 12, co-operate with the detent L so that the wheel E
is held against accidental displacement. At L' is shown one of the controller
contacts.
In operating a car or train equipped in accordance with our invention, the
motorman stations himself at one of the master controllers A, preferably at that
one which happens to be at the front of the car or train. He places the proper
handle upon the reversing switch, and throws it in one direction or the other,
according to the direction in which he desires the car to move. This causes the
cam wheel E (Fig. 5), to rotate, and unlocks the disks E, E2, thus allowing
the handles of the switches K and BS to be turned. This movement of the
reversing switch also sends current from the storage battery SB (Fig. 1), through
the reversing switch RS to one or the other of the coils C, C, and actuates
the motor reversing switch RS in the proper direction.
The next step is to turn the shaft S of the switch K. This cuts in the
resistances R, K³, R4 in multiple with the resistance R¹, as above explained, and
sends current to the contacts p², P², P³, PP and 24. Current now flows from
the trolley through the circuit breaker and contacts p', etc., through the
resistance R, and through the motors to ground.
Further rotation of the shaft $3 gradually reduces the resistance in series with
the motor, then increases it, makes the change to parallel, and, finally, short-
circuits the resistance. The car is now running at full speed.
Imagine now that it is desired to apply the brakes. The master reversing
switch is in the forward position, so that the cam E of Fig. 5 is in such a
position as to allow the disk E2 to be turned. But the disk E is in such a
position that the roller at the end of the arm F does not rest in the notch E,
but rests in a shallow notch. The result is that the nut f occupies the dotted
line position, so that the arm F is locked in the position shown in the drawing
by the contact of the two nuts f and f¹. It is, therefore necessary to return
the switch K to the off position, namely the position shown in the drawing.
When this is done, the reversing switch still remaining in the forward position,
the shaft S', Fig. 4, is rotated.
This causes the disk 3, Fig. 6, to slip upon the disk Es so as to bring the
contacts 20 in the dotted line position Fig. 1. This movement also admits
current to the brake motor M, though in series with the whole resistance R³.
This causes the motor to wind up the brake chain, but the resistance R prevents
it from exerting a very large torque. The motor M is purposely so built that
it is capable of becoming, and remaining, stationary at that point where the
torque necessary to put further tension on the brake chain is greater than the
torque furnished by the motor, with the resistance in the particular adjustment
in which it may happen to be.
Further movement of the switch shaft S₁ causes the resistance R³ to be gradually
cut out, and thus increases the torque upon the brake chain.
The brakes may be held at any desired tension by simply leaving the handle
of the switch BS at the proper point. If it is desired to reduce the tension
the handle will be moved in the off direction. This will cause the plate E³

page_text: to slip upon the plate E6, and will put the contacts 20ª in their full line position,
Fig. 1. This will cause the circuit of the motor M to be momentarily inter-
rupted, as each additional resistance is cut in, and will allow the motor M to
slip to a position corresponding to the torque which it is supposed to exert with
the additional resistance in place. Thus the gradual motion of the shaft S' in
the off direction serves to gradually release the tension upon the brake chain.
It will be noticed that the first rotation of the shaft S, and therefore of the
disk E, locks the reversing switch and also locks the power switch K. Further,
this rotation withdraws the cam 12, and leaves the dog F free to move to the
left in Fig. 5. It is therefore possible to apply the clutch MC by the operation
of the switch MS, in any operative position of the brake switch BS.
.
This is accomplished by the proper rotation of the handle S of Fig. 4. Such
rotation acts first to close the circuit of the clutch MC by the engagement of
the contacts 18 and 19 of Fig. 1 with the plates 18b19b. Just after these con-
tacts engage, as described, the contacts 17 and 18 leave the plates 17ª, 18ª, and
open-circuit the switch BS and the motor M. The brake is thus held in any
position in which it may happen to be. But, as above described, any motion
of the shaft S₁ of the switch BS in either direction to increase or decrease the
braking power, causes the switch MS to be automatically thrown to the position
illustrated in Fig. 1.
We have thus devised an arrangement, applicable either to a single car or to
a long train of cars, capable of controlling the apparatus for movement in
either direction at any required speed, or for braking with any desired gradation
or adjustment. It will be obvious that the various features of our invention
are not in any way limited to master controller systems, but may be used with
switches acting directly upon the motors. It will also be obvious that various
changes may be made without departing from the spirit and scope of the
invention.
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 The combination of a braking motor, a magnetic clutch, means for applying
the clutch when the brake motor has been actuated, and means for automatically
releasing the clutch when current is admitted to the brake motor.
2-The combination of a rotary electric motor acting upon the ordinary
brake-rigging of a car or moving load, a magnetic clutch for stopping the
rotation of the motor and holding it at any desired position, and means for
releasing the clutch when current is admitted to the motor.
3-The combination of a braking motor, with a magnetic clutch, means for
actuating the clutch, means for controlling the motor, and a device actuated by
the motor controller for releasing the clutch when current is admitted to the
braking motor.
4-A controlling device having a brake switch, and a switch for controlling
a magnetic clutch, with interlocking means between the switches such that the
switch for the clutch can be thrown only after the brake switch has been turned
on.
5-A controlling device having a brake switch, a switch for controlling a
magnetic clutch, means for locking the clutch switch until the brake switch is
turned on, and means actuated by the operation of the brake switch for auto-
matically releasing the clutch.
6-The combination of power switch, reversing-switch and brake switch, with
a switch for controlling a magnetic clutch, interlocking devices preventing the
simultaneous movement of more than one of the first three switches, and a
device preventing the movement of the magnetic clutch switch until the brake
switch has been operated.
The combination of a reversing switch, a brake-switch, and a switch for

page_text: operating a magnetic clutch, means for operating the switches independently,
interlocking mechanism between the reversing switch and the brake switch, and
mechanism permitting the movement of the clutch switch only after the brake
switch has left the "off" position.
8 The combination of a reversing switch, a brake switch, and a switch for
operating a magnetic clutch, all mounted upon a single shaft; means for operating
the switches independently, interlocking mechanism between the reversing
switch and the brake switch, and mechanism permitting the movement of the
clutch switch only after the brake switch has left the off" position.
9-The combination of a brake switch and a switch controlling a clutch, with
means for opening the circuit of the brake switch by applying the clutch, and
means, actuated by the movement of the brake switch, for automatically returning
the clutch switch to its off position and restoring the brake switch circuit.
10 The combination of a brake switch and a switch for controlling a mag-
netic clutch, with means for opening the circuit of the brake switch by the
application of the clutch.
11-The combination with a brake of a switch arranged by one movement to
gradually apply force to the brake, and by another movement to reduce the
force applied and, momentarily, to allow the brake to be released to quickly
adjust itself to the new force acting.
12 The combination with a brake of an electric motor for applying the brake
and a switch arranged by one movement to gradually apply force to the brake,
and by another movement to reduce the force applied and, momentarily, to
allow the brake to be released to quickly adjust itself to the new force acting.
13 The combination with a pair of constant potential mains, of a storage
battery with a resistance in series therewith connected across said mains, a
switch for applying the current from the battery to a useful purpose, and con-
tacts upon the switch adjusted to decrease the effective magnitude of the
resistance when the switch is closed.
14 The combination with an electric vehicle, of a storage battery in series
with a resistance connected to the source of supply of said vehicle, an electro-
magnetically controlled device for varying the motor circuits of the vehicle, a
switch for controlling the electromagnetically controlled device, and contacts
on the switch arranged to decrease the effective magnitude of the resistance in
series with the storage battery when the switch is closed.
15 The combination with an electric motor, of a controller for the motor, a
magnetic clutch for the motor, a switch for operating the magnetic clutch, and
connections so adjusted that the movement of the switch to vary the clutch
open-circuits the motor.
16 The combination with a mechanical brake of an electric motor for applying
the brake, an electro-magnetic clutch for holding the brake in any desired
position, and means for controlling the motor and brake from a selected point.
17 Two switches each connected on one side to a source of current, one
through contacts on the other, so arranged that when the second switch is in
the operative position, the supply of current to the first will be interrupted.
18 The combination with an electric motor, of a controller for the motor, a
magnetic clutch for the motor, a switch for operating the magnetic clutch,
connection's so adjusted that the movement of the switch to vary the clutch
open-circuits the motor, and an interlock arranged to open-circuit the clutch
when the motor controller is actuated.
19 In an electrically actuated train, the combination with a number of cars,
of motors on such cars, means controlled from a single point on the train for
connecting motors in series and parallel and varying the resistance of the motor
circuits, a number of auxiliary motors on the train connected to apply mechanical
brakes, and means controlled from a single point on the train for controlling
said auxiliary motors and varying their torque.
20 In an electrically actuated train, the combination with a number of cars,

page_text: of motors on such cars, means controlled from a single point on the train for
connecting the motors in series and parallel and varying the resistance of the
motor circuits, a number of auxiliary motors on the train connected to apply
mechanical brakes, means controlled from a single point on the train for con-
trolling said auxiliary motors and varying their torque, and means for holding
the auxiliary motors in any desired position.
21 In a switch the combination of a plurality of sets of moving contacts,
with means for shifting one of the sets so that the two sets are in different
relations in the opening and closing of the switch.
22 In a cylindrical switch, the combination of two sets of moving contacts,
with means for bringing the contacts into line as the switch moves in one
direction, and for changing their relation so that they are out of line as the
switch moves in the other direction.
23-In a switch, the combination of two sets of moving contacts, means for
bringing the two sets of contacts in a line as the switch moves in one direction,
and for bringing one set in line with the intervals between those of the other
set as the switch moves in the other direction.
Dated this 25th day of Ontahan 1000
THE BRITISH THOMSON-HOUSTON CO., LTD..
J. J. MANHEIM,
A. R. MONKS,
Directors.
ALFRED CLEMENTS,
Assistant Secretary.