Improvements in the Controllers of Electric Motors.
Year: 1899

page_text: Date of Application, 22nd Dec., 1899-Accepted, 14th Apr., 1900
Improvements in the Controllers of Electric Motors.
We, THE BRITISH THOMSON-HOUSTON COMPANY, LIMITED, of 83, Cannon
Street, in the City of London, Electrical Engineers do hereby declare the nature
of our said invention (which has been communicated to us from abroad by
Frank E. Case, 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 prformed, to be particularly described and ascertained
in and by the following statement:
It has sometimes happened, in the operation of electric and other motors,
and particularly in railway motors, that the motorman or engineer has become
injured or fainted from one cause or another, and has allowed the motor
train to run wild, with serious results.
or
In accordance with our present invention, we provide for this emergency by
a certain safety device which, when the motorman's attention is taken from his
work even if momentarily to such an extent as to make him remove his hand
from the controlling handle or lever, or relax his vigilance, shuts off the power.
Further, we provide a device making it necessary, after this has happened, to
bring the handle to substantially the off position before the power can again be
turned on.
It has been suggested to use on a controller, a powerful spring acting upon
the controller cylinder with sufficient strength to return it to zero when the
motor man releases the handle. This however, if the spring be strong enough
to effectually fulfil its purpose, takes considerable strength and in the course
of a long run becomes so exhausting to the motorman as to be entirely
impracticable.
For such methods we substitute a latch upon the controlling handle, which is
kept depressed so long as the motorman's hand rests upon the latter, the weight
of the hand being ample to hold it so that it requires but little muscular
exertion. If however the hand be removed even momentarily, and automatic
device is operated independent of the position of the controlling handle which
robs the motor of power. A subsequent pressure upon the latch does not how-
ever restore the power, but the controlling handle must be brought to- the off
position, and its proper manipulation in turning on will again admit the power.
With this arrangement, when applied to electric motors, we may combine
(and by preference do use) a current-measuring coil in the main circuit, which
shall act upon the same circuit-breaking contacts, so that if at any time an
excessive current flows, as when a short-circuit occurs in the apparatus, the
circuit-breaker will be opened and damage prevented as far as possible. In
practice the circuit-breaker should be so arranged that only an excessive
current and one which could seriously damage the apparatus will operate it.

page_text: •
:
In the accompanying drawings, which show an embodiment of the invention,
as applied to an electric railway car, Fig. 1 is a front elevation, with parts in
section and with the cover removed, of a controller to which the invention is
applied Fig. 2 is a plan on the section line 2-2 of Fig. 1; Figs. 3 and 4 are
enlarged detail views; and Fig. 5 is a diagram of circuits, not however showing
the circuits of the controller, since the invention is independent of these.
In Fig. 1A is the controller frame, and B is the handle which operates the
controller cylinder G to make the connections with the various contacts G¹ in
the usual way; it is provided with the insulating disc G2 preventing the arc
jumping from the controller contacts to the other mechanism, and with the
usual star-wheel G³ to determine the proper position of the controller. These
parts are all well understood, and require no detailed description.
Upon the shaft of the controller is mounted a sleeve D. A projection d
from the sleeve contains a slot in which one end of the lever Centers when the
other end is pressed by the pin C. A button B₁ controls the pin and holds it
down against the power of the spring c while the hand of the motorman rests
upon the handle. The spring c is made as light as is consistent with its office,
and inasmuch as the weight which it has to move is very small, it may be made
quite flexible so that the weight of the hand and arm is ample to hold down the
button B as long as may be necessary. A spring E is enclosed within a
housing D¹ forming part of the sleeve, one end of it being secured to the sleeve
and the other to a pin E¹ projecting from the top of the controller. The office
of this spring is to throw the sleeve forcibly to the off position whenever the
end of the lever releases the lug d. It is plain that this spring may be of
much less power than if it were intended to turn the controller cylinder against
the friction of the brushes and step-by-step device.
Referring now to Figs. 2, 3 and 4, D2 is a toe formed upon the sleeve D,
from which the cam plate D³ projects. This registers with the toe 12 of the circuit-
braking contact I; this toe is pivoted to the lever or contact I, and a lug
upon it engages with a corresponding projection so that when the toe Is moves
up it will move the lever I; but the toe may be moved down freely, a spring ở³
restoring it to its proper position. The contacts K, K are bridged by the con-
tact I, which is prevented from moving too far by a stop i. A series coil H is
included in the circuit, the armature h' of which is fixed to a pawl H¹ which
engages with a projecting arm I holding the latter so as to close the con-
tacts K, K when the device is set. A pin h upon the cam plate D³ operates
the pawl against the spring h² when the controller is brought to the off position.
An arm M carries the intercepting shields L of the controller, the usual blow-
out magnet being provided; and an additional part L' is arranged upon this
arm so as to afford a suitable blow-out for the contacts K, K.
The operation of the device as thus described is as follows: When the con-
troller handle is moved to the right, the cam-plate D3 is turned and the toe D³
presses upon the pivoted toe 12, throwing the contact I so as to bridge the con-
tacts K and moving the arm I so that the pawl H¹ engages with its end and
holds the contacts closed. Whenever the controller is at one of its running
positions, the usual pawl (not illustrated) falls in one of the notches of the
star-wheel G³. So long as the lug d engages the end of the lever C¹, most of
the power of the spring E is opposed by the step-by-step device so that com-
paratively little strength is needed to hold the controller in its position. If
however the button 13 be released the end of the lever C is withdrawn from the
lug and the spring snaps the sleeve around independently of the motion of
the controller cylinder. The pin h then engages with the pawl Hand re-
leases the arm I¹. A spring I³ (see Fig. 1) then throws over the contacts K
by moving the bridging contact I, and the blow-out magnet ruptures any arc
which may tend to form. At this time the lug or toe 12 will be beyond or to
the right of the toe I'.

page_text: To reset the device the controller will be turned to the position illustrated
in Fig. 2. In doing so the projection 12 will turn the toe 12 about its axis
against the spring I, as shown in dotted lines (see Fig. 3). As soon as the
projection Da clears the toe, it suaps into the illustrated position, and when the
controller is again turned on, the lug 2, engaging with a projection from the
lever I, resets the latter, while the spring, when the pin h is withdrawn, forces
the pawl H¹ into engagement with the arm I', as already described.
In Fig. 5 the circuits of the device are illustrated. It will be seen that the.
coil H is in series between the trolley T and the contacts K, K, one of which
is connected to the upper or trolley contact G₁ of the controller, as shown in
Fig. 1. When this arrangement is used it is manifest that when the circuit
is completed through the motors N, N', any excessive current in the coil H
will draw up the armature h' and release the pawl H¹; the circuit-breaker will
immediately open. It may however be reset by the manipulation of the con-
troller handle in the way already pointed out.
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, with a controlling device for electric currents, of a
circuit-opening device, means for closing the circuit at the circuit-closing
device actuated by the revolution of the controller, and means, brought into
action by releasing the controller handle, for opening the circuit.
2-The combination, with a controller for electric circuits, of a circuit-open-
ing device, means for closing the circuit-opening device actuated by the first
movement of the controller from its off position, and means, brought into action
by the release of the controller handle, for opening the circuit-opening device.
3-The combination, with a controller for electric circuits, of a circuit opening
device, means for setting it actuated by the first movement of the controller
from its off position, means for opening the circuit-opening device, brought into
action by the release of the controller handle, and means for opening the same
device operated by excess of current in the controller circuit.
4-The combination, with a controller for electric circuits, of a circuit-breaker
in series with the controller, means for opening the circuit at desired times,
and a connection between the controller and the circuit-breaker, such that the
first movement of the controller after reaching its off position resets the circuit-
breaker.
5 The combination with a controller for electric circuits, of a circuit-breaker
in series with the controller, means for opening the circuit-breaker at desired
times, and a cam upon the controller shaft for resetting the circuit-breaker
when the controller starts from its off position.
6-The combination with a controller for electric circuits, of a spring-actuated
cam upon the controller, a circuit-breaker in series with the controller, means
actuated by the handle of the controller for revolving the cam and setting the
circuit-breaker, and means, brought into action by the release of the controller
handle, for releasing the cam and permitting the spring to open the circuit-
breaker.
7-The combination with a controller, of a sleeve upon the controller shaft.
a connection from the controller handle to the sleeve such that when the con-
nection is brought into play the sleeve revolves with the controller, a cam
actuated by the sleeve, and a circuit-breaker operated by the cam; the arrange-
ment being such that when the connection between the sleeve and the con-
troller handle is released, the cam revolves and opens the circuit-breaker, and
when the sleeve is engaged by the handle, the cam when revolved sets the
circuit-breaker only after the controller has been returned to its off position.

page_text: 8-In a device for regulating the application of power, a controlling handle,
and means controlled from the handle for shutting off the power independent
of the position of the handle.
Hated this 19th day of Doomben 1800
THE BRITISH THOMSON-HOUSTON CO., LTD.,
ALFRED CLEMENTS,
Assistant Secretary.
J. J. MANHEIM,
T. R. THOMPSON,
Directors.