US1969576A - Electric switch operating mechanism - Google Patents

Description

Aug. 7, 1934. R. PAXTON 1,969,576

ELECTRIC SWITCH OPERATING MECHANISM Filed Nov. 30. 1931 Inventor; Robert; Paxton,

His Attow-hes Patented Aug. 7, 1934 ELECTRIC SWITCH OPERATING MECHANISM v Robert Paxton, Drexel Hill, Pa., assignor to General Electric Company, a corporation of New York Application November 30, 1931, Serial No. 577,880

2 Claims.

My invention relates to electric switch operating mechanism, more particularly to mechanism for eifecting selective operation of circuit breakers as in single phase switching.

A polyphase electric power transmission system may, under certain conditions, be controlled to advantage by selective operation of the single phase circuit breakers. This selective control known as single phase switching may be of particular value in maintaining continuity of service as in .the case of a temporary single phaseto-ground fault. In -polyphase systems wherein the phase circuit breakers are tied together by a common operating mechanism and close and i5 trip in unison, a phase-to-ground fault would result in complete interruption of the supply. In case of single phase switching, however, it is possible to trip out the breaker in the phase having a temporary fault and carry the unbalanced load on the remaining phases for a limited time. In

the meantime the fault may have cleared permitting reclosing of the breaker.

The principal object of my invention is the provision of improved mechanism for single phase switching.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which.

characterizemy invention will be pointed out with particularity in the appended claims forming a part of this specification.

Referring to the drawing, Fig. 1 is a view, partly in perspective, of operating mechanism embodying my invention, and Fig. 2 is an enlarged fragmentary view'of details shown in Fig. 1.

In the arrangement shown, a circuit breaker generally indicated at 1 comprises one of the phase breakers of a three phase power transmission system. Since the construction and operation of the other breakers are identical, a de tailed disclosure and description thereof may be omitted in the interest of clearness. The operating mechanism for the circuit breakers is generally indicated at 2 and comprises suitable motive means, as an electric motor 3, for transmitting movement to the switch mechanism through the well known centrifugal or flyball operator 4.

To this end the flyball operator 41s pivotally connected to a crank 5 which is suitably keyed or pinned to the main operating shaft 6. Energization of the motor 3 and extension of the rapidly rotating fiyball linkage causes counterclockwise rotation of the shaft and-tensioning of a spring "I, which is fixed at one end '7' and connected at the other end to a lug a likewise pinned on the shaft 6. The flyball linkage 4 is shown in the initial or reset position towards which it is normally biased by the resetting spring 7. In

other words, the spring -'7 effects resetting of the extended flyball linkage after each circuit closing operation.

For the purpose of transmitting closing movement from the main shaft 6 to the breakers of the respective phases indicated by A, B, and C, a plurality of toggles, one for each breaker, are arranged to be straightened to an overset locking position by rotation of the, shaft 6, each toggle being free to collapse and permit opening of the corresponding breaker independently of the other toggles. To this end, the breaker 1 of B phase, for example, is operatively. connected to the shaft 6 by a toggle 9-10, the toggle arm 10 including a collar 11 which is mounted to free rotative movement on the shaft 6. The toggle joint 12 is locked in the overset position by the offset lug 13 carried by the arm 10 so that an'initial tripping impulse is necessary'to cause collapse of the toggle. The toggle arm 9 is connected to the switch actuating rod 14 through a bellcrank 15 pivotally mounted on a fixed shaft 16. The tripping impulse may be applied in any suitable manner, a tripping solenoid 17 being shown by way of example for this purpose. The tripping mechanism shown is simplified in the interest of clearness since it forms no part of the present invention. It will therefore be apparent that the mechanism connected to the individual, breakers may be of the well-known trip-free type.

For the purpose of permitting tripping andreclosing'of a single breaker irrespective of the fact that the other breakers remain closed, a lost motion connection is provided between the shaft 6 and the individual toggles. This lost motion connection comprises, in the case of the B phase toggle, an offset lug or equivalent member 18 secured to the crank .5 and arranged to engage the toggle arm 10 in closing the breaker. The lost motion connection for each of the phases A and C includes a collar 19 pinned as at 20 to the shaft 6 and provided with an offset lug 21 for engaging the corresponding toggle arm 10. This construction is best shown in Fig. 2 wherein the parts are spaced in order clearly to illustrate the manner of cooperation.

It will be noted that the toggle arm 10, which is loosely mounted on the shaft 6, is positively driven in but one direction by the lug 21 carried by the fixed collar 19. Rotation of the shaft 6 in the opposite direction simply moves e the lug 21 away from the toggle without at- Iecting the position of the same.

Assuming, therefore, the toggle of the B phase mechanism to be in the position shown, the other toggles being closed, energization of the motor 3 and extension of the fiyball linkage 4 will cause rotation of the crank 5 and straightening of the toggle 9-l0 through the connection above referred to. The collars 19 associated with the toggles of the A and C phases merely rotate without engaging the corresponding toggle arm. As the toggle is straightened the-actuating rod 14 of the B phase breaker is lowered, causing closing of the breaker.

Any suitable type of breaker may, of course, be employed, and by way of example there is shown a circuit breaker of the explosion chamber type comprising a vertically movable bridging member 22 coacting with the stationary contact structure within so-called explosion pots 23 and 24 separated by an insulating bracing member 25. The lift rod 26 of the breaker is connected to the actuating rod lithrough the well known parallel linkage mechanism 27. The above circuit breaker structure is mounted in a manner well known in the art in a steel tank'containing oil.

The operation of the mechanism may be summarized as follows: Assuming the polyphase system to be in normal operation and all three breakers closed, the corresponding toggles 9--10 will each be in the overset locking position and the fiyball linkage 4 will be in the deenergized reset position. In the event of a phase-to-ground fault on B phase for example, the tripping solenoid 17 is energized, kicking the corresponding toggle over-center and causing collapse thereof to the position shown. The collapse of the toggle is assured by forces, as gravity for example,

normally biasing the circuit breaker towards open position. Since the lug 18 is in the reset position, the toggle 9--10 is free to trip open in-- dependently of the other toggles. Clearance of the fault within a short time permits reclosing of the B phase breaker which may be readily accomplished by energizing the motor 3 and straightening the toggle 910 ofthe open breaker. Closing of the B phase breaker is effected by the motor independently of the other breakers since the collars 19 may rotate to the completely closed position before the lugs 21 engage the corresponding toggle arms 10. In the same manner the breakers may be closed simul taneously, after which the motor 3 is deenergized and the operating linkageii'is reset so that selective reclosure of the phase switches may be effected.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as'new and desired to secure by Letters Patent of the United States is:

1. Polyphase switch operating mechanism for a plurality of single phase circuit breakers comprising an operating motor, means including a plurality of toggles and a shaft actuated by said motor operatively connecting said motor to each of said breakers, means secured to said shaft for engaging only the toggles of breakers to be closed, rotation of said shaft in one direction causing straightening of one or more of said toggles, and resilient means biasing said shaft independently of said toggles in the opposite direction for resetting said mechanism after said toggle operation.

2. Switch operating mechanism for a plurality of single phase circuit breakers comprising a motor and centrifugal operating linkage, a shaft directly connected to said linkage arranged to be rotated in one direction upon extension of said linkage, an actuating toggle for each breaker operatively connected between the same and said shaft, each toggle having an arm mounted for free rotative movement on said shaft, lugs individual to each toggle fixed to said shaft for moving the corresponding toggle arm to the straightened position, a tripping solenoid coacting with each toggle for causing collapse thereof, and a spring for rotating said shaft in the opposite direction to its initial position after deenergization of said operating motor.

ROBERT PAXTON.

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