US873815A - Switching device for electric motors. - Google Patents

Description

PATENTED DEC. 17, 1907. J. B. WIARD.

Fie. I.

INVENTEJR JDHN E1. WIARD, BY 4 ATT'Y.

SWITCHING DEVICE FOR ELECTRIC MOT APPLICATION FILED MAY 23,1907.

BEES:

WITNE UNITED I PATENT OFFICE.

JOHN B. WIARD, or LYNN,

swrrcnme nnvxcn ron ELECTRIC morons.

To all'whowl it concern: I,

Be it known that 1, JOHN swim), a citizen of the United States, residing at Lynn,

vices centrifugally actuated havefrequently heretofore for electric motors, and particularly for single-phase induction been employe motors which require special startin con nections.- In all such devices with w ich I am familiar centrifugal force has been employed directly to actuate the automatic switch.

My invention consists in employing cen trifugal force simply to control the actuation of the switch and employing the momentum of the rotor for the actuating forge.

By my invention the size of the centrifugal device is reduced to a minimum, and its construction may be the simplest possible, -while the switch itself may be of simple construction without sliding contacts or complicated mechanical construction.

My invention will best be understood by reference to the accompanying drawings, in which I Figure 1 shows a side elevation, with the casing partly broken away, of an electric motor provided with an automatic switching device arranged in accordance with m invention; Fig. 2 shows an and elevation o the motorwith the end-plate and bearing removed; Fi 3 -shows a view of the automatic switc in running position; and Fig. 4 is a diagramof the motor circuits with the starting switch shown in perspective.

In the drawings, A represents the stator carrying the primary coils a.

B represents the rotor on which is pivotally mounted a centrifugal weight when the motor is at rest,is held ag motor shaft, in the position shown 1n Figs. 1 and 2, by the spring D.

c is a pm or projection carried by the cen trifugal weight. I, I Y

E represents a member pivoted at F on the motor-bearing and having two projections e Specification of. Letters Patent. I Application filed Hay 2a. 1907. Serial No. 876.196.-

C, which,

ainst the move the switch. Furthermore,

Patented. Dec. 17, 1907.

and 0 extending into the plane of rotation of the pin c.- L

G represents a contact-piece carried by the member E and .adapted to bridge the stationarycontacts H-when the member E is in the position which, it occupies at starting. The contacts H are in series with the starting windin of the motor, as shown diagrammatica ly in Fig. 4, in which 0, represents the main winding, a the starting winding, and I anon-inductive resistance or other suitable phase-controlling means to produce a phasedis lacer'nent between the currents in the coi s a and a at starting.-

MASSACHIISE'ITS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A QORPORATION-OF NEW YORK.

At starting, the centrlfugal weight C and member E are in the positions shown in Fig. 1, so that the contacts H are bridged by the contact member G, and the circuit of the starting winding is closed. As the motor speeds up thecentrifugal weight 0 is thrown outward to bring its tail-piece against the motor shaft, bringing the .pin c-into engagement with the convex inner side of the projection e and pushing the projection outward beyond the path of rotation of the pin at high s eed, hereby rocking the member E into the position shown in Fig. 3. In this position the contact G is out of engagement with the contacts II and the starting'circuit of the motor is'open. The member E remains in this osition until the motor is stopped. In slowing. down,- the centrifugal weight C is drawn inward by spring D, so that the pin 0 is brought into engagement with the convex outer surface of the projection e and pushes it inward beyond the path of rotation of the En at low speed, thereby returning member to its starting position:

. It will be seen that the centrifugal weight C merely controls the actuation of the switch by altering the path of rotation of the pin 0.

For moving the switch, the momentum of the rotor is employed, which causes the pin to strike a sharp blow on the projectin pieces 6 and e. The size of the centrifuga weight mayconse uently be smaller than if centrifugal force a one were relied upon to the switch is stationary, so that all slidingcontacts'are avoided. i

To hold the member E in either position to which it is moved, spring washers f or other suitable friction devices may be employed, as shown in Fig. 2. Furthermore,

the member E may be so designed that its center of gravity is shifted from one side to passing through by Letters Patent of the United States, is,

controlling the starting 1. In an electric motor, a centrifugally actuated member carried by-the rotor, a device carried by the stator adapted to be engaged by said member 'in a 'redetermined position thereof and moved byt he momentum of the rotor, and switch contacts actuated by said device controlling the starting connections of the motor.

2. In an electric motor,-a member carried by the rotor and adapted to have its path of rotation altered by centrifugal force, a device carried by the stator adapted to be engaged by said member in one of its rotational aths, and switch contacts actuated by said evice connections of the motor.

3. In an electric motor, a member carried by the rotor and adapted to have its path of rotation altered by centrifugal force, a device carried by the stator having two portions pro-. jectin respectively into the rotational aths of sai member at starting and at spec ,and

switch contacts actuated by said device controlling the starting connections of the motor.

4. In an electric motor, a member carried by the rotor and movable W ith respect thereto by centrifugal force, a rojection on said member extending at rig t angles to the direction in which said member-is moved by centrifugal force, a device carriedby the st ator ada ted to be engaged by said projection in a pre etermined position of said member, and

switch contacts actuated by said device controlling the starting connections of the motor; ;5. In an electric motor, a member car ried by the rotor and movable outwardly from the rotor axis by centrifugal force, an axiallyextendingprqection on said member, a device adapted to be engaged by said rojection in a pre etermined position of sai member, and switch contacts actuated by said device controlling the starting connections of the motor.

6. In an electric motor, a pivoted device 1 ing connections of the'motor.

7. In an electric motor, a pivoted device carried by the stator having two projections displaced from each other radial y spect to the rotor, the outer projection having a convex inner surf ace, and the inner projection having a convex outer surface, a member carried b the rotor movable radially by centrifugal fbrceto engage-said rojections re spectively at starting and at ll speed, and

with re- I switch contacts actuated by said device con--' trolling the starting connections of the motor. In witness whereof, I have hereunto set my hand this twentieth day of May, 1907.

JOHN B. WIARD. Witnesses:

JOHN A. MCMANUS, Jr, I-InNRr Q. WESTENDARP.

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