Improvements in controшing Switches for Electric motors.
Year: 1899

page_text: Improvements in controшing Switches for Electric motors.
I, HARDMAN ARTHUR EARLE, of Salford Iron Works, Manchester, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the construction of the switches employed for start-
ing stopping and varying the speed of electric motors, in such a manner that a
single set of contacts and resistances serve for controlling the motor in either
direction of its motion.
For this purpose, an operating lever is provided with a sliding catch which,
when the lever is moved quite over toneither hand, can engage the one or the
other of two contact levers which are pivotted on each side of the operating
lever; and then, on moving the operating .lever, the contact lever which is
engaged is moved with it over the resistance contacts. The sliding catch can be moved
by hand, but it is also connected to the core of a solenoid which automatically
disengages it, and thereupon the contact lever which it had engaged, is returned
to its zero position by a weight on an arm projecting from it. On the side of
cach of the contact levers is fixed an insulating conducting block which, when
the lever is in zero position, connects a pair of contacts and so completes the
circuit between the field magnet coils of the motor and the line of resistance
contacts.
Dated this 11th day of March 1899.
ABEL & IMRAY.
Agents for the Applicant.
COMPLETE SPECIFICATION:
Improvements in Controlling Switches for Electric Motors.
I, HARDMAN ARTHUR EARLE, of Salford Iron Works, Manchester, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention 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 the construction of the switches employed for start-
ing stopping and varying the speed of electric motors, in such a manner that a
single set of contacts and resistances serve for controlling the motor in either
direction of its motion.
For this purpose, an operating lever is provided with a sliding catch which,
when the lever is moved quite over to either hand, can engage the one or the
other of two contact levers which are pivotted on each side of the operating
lever; and then, on moving the operating lever, the contact lever which is
engaged is moved with it over the resistance contacts. The sliding catch can be moved

page_text: by hand, but it is also connected to the core of a solenoid which automatically
disengages it, and thereupon the contact lever which it had engaged, is returned
to its zero position by a weight on an arm projecting from it. On the side of
cach of the contact levers is fixed an insulating conducting block which, when
the lever is in the zero position, connects a pair of contacts and so completes the
circuit between the field magnet coils of the motor and the line of resistance
contacts.
Fig. 1 of the accompanying drawings is a front view and Fig. 2 is a side view
of a switch according to my invention. Fig. 3 is a diagram of the electrical con-
nections.
13 B are the two contact levers, L the operating lever on which is fitted a
sliding catch P that can be raised by grasping the lever p. Each of the contact
levers B has a projecting pin C so that when the operating lever is moved right
over to either hand the catch 1' embraces the pin C and then on raising the catch so
that the pin C is engaged in its hollow the two levers B and L can be moved
together.
Rare a number of resistance contacts with any one of which the end of either
lever B can make contact as it rubs over them. Each of the contact levers B
has fixed on it a conducting block E which is insulated from the lever itself, but
when the contact lever B is in its normal or zero position this block E makes con-
tact with the pieces F and G.
As shewn in Fig. 3, each of the contact levers B B is permanently connected to
one of the terminals of the armature A of the motor. The resistance contacts R
are connected to their respective resistances the two last being connected to the
contact FF. The contact G G are both connected through the coil N of the
field magnet of the motor to one of the lines Q. The contacts b b are both con-
nected to the winding of the solenoid M the other end of which is connected to
the other line.
The circuit when the switch is in use is as follows:
From the line Q through the contact piece G and the block E to the other
conducting piece F then to the resistance R and through the one lever B and the
motor armature A to the other lever B to the contact b thence from there through
the winding of the solenoid M to the other line. There is a like circuit which-
ever of the contact levers B is moved but the direction of current in the motor
armature is reversed.
Each of the contact levers B is loaded with a weight W which pulls the con-
tact lever over to its zero position when the pin C is released by letting go
the handle p. The catch P may be urged upwards by a spring the lever p being
so pivotted that on grasping it the catch is depressed. When this arrangement is
adopted the catch P is attached to the core of the solenoid M by a cord passing
under guide pulleys. When the core is drawn into the solenoid M the motion is
communicated by the cord to the catch P which is drawn down thus releasing the
pin C as before and cutting off the current.
The winding of the solenoid is connected in series with the motor armature and
magnets and is adjusted to pull the core in when the current exceeds a certain
fixed amount.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is :-
A controlling switch for an electric motor constructed and operating sub-
stantially as described.
Dated this 11th day of Tanum 1000
ABEL & IMRAY,
Agents for the Applicant.