Improvements relating to the Regulation of Electric Motors and to the Brakes for Electric Railway Vehicles and the like.
Year: 1899

page_text: Date of Application, 30th Oct., 1899-Accepted, 27th Jan., 1900
Improvements relating to the Regulation of Electric Motors and to the
Brakes for Electric Railway Vehicles and the like.
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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 Frank E. Case,
residing at Schenectady, County of Schenectady, in the 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:―
The present invention relates to the regulation of electric motors particularly
to those used on electric railways; and has for its object to provide means for.
increasing the efficiency of the system by utilizing in part at least, the energy
which ordinarily is wasted in the starting or running resistances. To attain this
object there is substituted for a part of the regulating resistance a suitable
motive device which by its resistance, self-induction and counter electromotive
force will reduce the current flowing to the main motors, but which instead of
wasting energy, may accomplish some useful auxiliary purpose, such as storing
energy, as by running an air compressor, for instance for operating the brakes.
We are also able by our improvements to positively release the brakes at starting,
and to accomplish other useful results.
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The invention is illustrated in the accompanying drawings; in these, Fig. 1 is
a diagram of circuits of a suitable controller; Fig. 2 is an illustration in diagram
of the device used for releasing brakes; Figs. 3 and 4 are a horizontal section,
and an end elevation partly in section respectively, of the device shown in Fig. 2.
Fig. 1 illustrates a well known form of controller, known in the art as the
"K controller. It is immaterial what form of controller is used, but this is
one well adapted to the invention. The contacts are numbered 1 to 11 respec-
tively, and the contact plates are correspondingly designated from 1 to 11b;
the reversing switch is shown on the right, its contacts being numbered from 12
to 19, and the contact plates correspondingly numbered as above described. The
various circuits will not be traced, as they will be apparent to those skilled in
the art, and the particular combinations are not essential to the invention. The
general operation of the controller is to couple the motors in series with a
resistance, in its first position, and to gradually cut the resistance out in
subsequent positions, until when the contacts S to 11 make contact respectively,
with the contact plates 8" to 11b, a shunt is thrown around the second motor,
with part of the resistance included in series; the shunt is broken as the con-
tacts 8, 9 pass off their contact plates, and the motors are thrown in multiple,
with full resistance, as contacts 7, 8 touch the plates 7b, Sb; further rotation of
the controller again cuts out resistance.
The reversing switch shown simply acts to reverse the connections between.
armatures and fields, and need not be more particularly described.
The circuit in the first controller position is as follows:-From trolley T,

page_text: to contact 1, contact 2, through the resistance R, to the motor M (to be presently
referred to), through the reversing switch to contact 18, through armature A₁,
through the reversing switch to contact 16, through field F¹, back to the controller
contact 9, contact 8, through the reversing switch to contact 14, through arma-
ture A, through the reversing to contact 12 and through field F to ground at G.
Thus it will be seen that the small motor M is included in series with the
resistance R and, in effect, forms a step of the resistance. To operate to the
best advantage, this motor should be one of comparatively high ohmic resistance,
so that practically it will act as a dead resistance in the circuit and cut down
the current even before it gets up its counter electromotive force. We have
illustrated the motor M as geared to a compressor C, and pumping air into a
reservoir R¹. It will be manifest thus that whatever energy is consumed by the
motor will be, so far as the motor efficiency permits, stored in the tank R and
not simply wasted in heat, as in the ordinary resistances. The compressed air
may particularly when the motor to be regulated is placed upon a railway car
or train, be utilized for braking purposes. We have illustrated at R² the air
brake mechanism, which may be of any preferred type, acting upon the brake
rods Q. It is further manifest that the principle just indicated might be carried
out to a considerable extent by the duplication of motors of the class designated.
This we have thought unnecessary to illustrate or describe, because it would be
readily understood by engineers.
In Figs. 2, 3 and 4 there is shown another device for accomplishing in another
way, the same useful results. In Fig. 2 L is the car wheel, and P is the brake
shoe mounted thereon, controlled by the brake rod Q. This brake rod is
attached to an eye D2 formed in the end of the core or shaft D. This connection
is shown as inade through a lever Q and a floating linkage, as usual, so that a
movement of the core or shaft D to the right will apply the brakes at both ends
of the car, and a corresponding movement to the left will release them. The
details of this linkage, which is similar to that shown in Fig. 1, are well known
in the art and need not be illustrated. The spring D) is so placed on the shaft
as to tend always to set the brakes powerfully on the wheels, by moving the
core D to the right in Fig. 3.
Mounted upon the same base A with the enclosing shell is a metal piece, B¹,
preferably of soft iron, enclosing a solenoid B, which, when energized, tends to
draw the core to the left. It thus appears that when current flows through the
solenoid coil the brakes are released, while at other times the spring tends to
cause them to engage the wheels. A stop and bushing are provided, as
shown.
Fastened to one end of the core or shaft D), or integral therewith, is a wedge D'
which slides between two stops ³, h. These stops are pierced with an opening
in which screw threads are cut and are mounted on the shaft H, provided with
reversely cut threads 2. This construction is well shown in Fig. 4. The
arm F mounted on the shaft H is connected to a spring K, which tends always
to rotate it in a right handed direction, and is further connected through the
link L and bell-crank lever N to a stud 0, preferably placed upon the front
platform of the car.
The electrical connections need not be shown in detail, since the coil B simply
takes the place of the motor M in Fig. 1, or is in some other way interposed in
place of a resistance step, but this coil should preferably be so placed that it is
energized the moment the controller is thrown to such a position as to start
the car in either direction.
Assume now that the parts are in the position shown in Fig. 3. The car is
assumed to be running, and current is flowing through the solenoid B. If, now,
the motors be speeded up, by- cutting out all the resistances, it is evident that
the solenoid will be de-energized. This would tend to set the brakes, but this
action is prevented by the wedge D³ and the stops h³, h, which bear upon it,
since it is obvious that in order to set the brakes it is necessary that the stops h³, h³

page_text: be separated which would involve a partial rotation of the arm F against the
spring E. The parts will therefore, remain in the position shown, utterly
irrespective of any change which may take place in the motor connections.
When it is desired to stop the car, the motorman simply presses the stud
which, acting through the bell crank lever N, and the link L, causes a partial
left-handed rotation of the arm F. This rotates the shaft H and allows the
stops h, h to separate. The spring 1 is then able to apply the brakes. It will
be seen that it is possible in this way to apply the brakes suddenly to their full
extent or, it is possible to release the spring D¹ only by a certain small amount,
as preferred.
The brakes, once set, will remain in position as long as desired, but the moment
that the controller is moved, to start the car, the solenoid B is immediately
energized and attracts its armature D in such a way as to produce a positive
disengagement or release of the brakes. At the same time, energy is restore:
by the compression of the spring D' sufficient to operate the brakes when it again
becomes necessary. This device provides, therefore, means for positively dis-
engaging the brake shoes at the time of starting the car, dependent upon and
actuated by the current in the motor circuit; such means acting also, in the
arrangement illustrated as a part of the necessary controlling resistance, and
being ordinarily cut out after it has performed its office. By the positive dis-
engagement or release of the brake shoes we mean a power actuated release,
positively overcoming frictional or other accidental obstacles. With it we com-
bine auxiliary means for retaining the brake shoes in their retracted position,
and this is, by preference, under the control of the motorman; and also an
automatic device for applying the brakes, under control, but not dependent
upon hand power. It will be apparent that as the wedge D3 is maintained by
the springs in contact with the nuts 3, 4, operated by the worms 1, 2, the
spring D is so far under the control of the detent for the brake releasing
mechanism, that its force may be utilized to apply the brakes to any desired
degree. As the stud is pressed down, if it be pressed lightly, for instance,
the spring will barely cause the engagement of the shoe with the wheel so as to
have but slight retarding effect; while, if the stud be pushed down so that the
worms are rotated sufficiently far. the wedge D³ will be released altogether, and
the spring will act to supply the brake shoes with any desired force, according to
its strength. One object of keeping the detent for the brake shoes under direct
control of the motor-man is to prevent the automatic application of the brakes
when the retracting device is cut out, which otherwise would occur.
Having now particularly described and ascertained the nature of our said
invention (as communicated to us from abroad) and in what manner the same
1s to be performed, we declare that what we claim is:-
-
1-In combination with the controlling means of an electric apparatus, such as
a motor or motors, a circuit including a resistance, formed in whole or in part
of a current actuated motive device, included as a step of the resistance.
2-A circuit, a resistance therein, a current actuated motive device included
as part of the resistance and a switch for cutting in or out at will the resistance
sections.
3-A circuit, a resistance therein, a current actuated motive device included
as part of the resistance, and a switch for cutting in or out at will the resistance
sections and the motive device.
4--A circuit including electric apparatus to be regulated, a resistance in the
circuit, a current actuated motive device included as part of the resistance, and a
switch for cutting in or out the resistance sections.
5 A resistance divided into sections, an electrically actuated motive device
included in the circuit as a resistance section, electrical apparatus regulated by
the resistance, and means for utilizing the energy absorbed by the motive device.
G-The combination of a motor or motors driving a load, such as an electric

page_text: car or train, a controlling device for the motors, a motive device included as
part of the controlling resistance, and means for utilizing the energy absorbed by
the motive device.
7 The combination of a motor or motors driving a load, a resistance, a
controlling device, a brake for the load, and a motive device for positively
releasing the brake at starting, included as a section of the regulating resistance,
and operated by the controller.
S-In the art of regulating electric motors, such as those driving a car or
train, a controller, a brake for the load, and electrically operated means for
positively releasing the brake, operated by the controller.
9--The combination of a motor or motors driving a load, a controlling device,
a brake for the load, means for positively releasing the brakes at starting the
motors, and means for retaining the brake out of engagement with the wheels.
10 The combination of a motor or motors driving a load, a controlling
device, brakes for the load, and means actuated by turning on the controller,
for positively disengaging the brakes, with a detent under the control of the
motorman, for retaining the brakes out of engagement with the moving load.
11 The combination with a number of motors driving a load, such as a car or
train, a controlling device for the motors, a brake, means actuated by the current,
and controlled by the controller, for positively disengaging or releasing the
brake, a detent for holding the brake out of engagement, and means for auto-
matically applying the brakes, controlled by the detent and applied when the
latter is released.
12 The combination of power mechanism driving a vehicle or other lead, a
regulator for the power, a brake, and means actuated by the power and controlled
by the regulator for positively releasing the brake.
13 The combination of a power actuated mechanism driving a load, a brake
for the load, a detent for holding the brake out of engagement, and means, con-
trolled by the detent, for applying the brakes with desired force.
14 The combination of power actuated mechanism, such as an electric motor,
driving a load, a brake, means operated by the driving power for positively
releasing the brake, a detent holding the brake out of action after its release,
and automatic means controlled by the detent for applying the brake with force.
15 The combination with an electric car of a motor and brake therefor, and a
regulating means for the motor acting to store energy to operate the brakes.
16 The combination with an electric car of a motor and brake therefor, a
regulating motor driving a pump to store energy for the brakes, and means for
coupling the regulating motor armature in series with the main motor armature.
Dated this 25th day of October 1899.
THE BRITISH THOMSON-HOUSTON Co. LTD.
J. J. MANHEIM,
A. R. MONKS,
ALFRED CLEMENTS,
} Directors.
Assistant Secretary.