Westinghouse Electric Corporation

Jack G Hanks

John F Cotton

Raymond E Wien

James O Rexroad

Jerome K Wolfe

A secondary circuit breaker for a distribution transformer characterized by electrical inductive apparatus within an oil-filled housing, and circuit interrupter for controlling current flow through the transformer and comprising a releasable latch arm, trip means operable upon overload conditions to release the latch arm, a latch lever between the trip means and the latch arm and comprising the only operable part therebetween, and the latch lever having a cam surface for latching and unlatching the releasable arm.

Secondary circuit breaker for distribution transformer

Retractable secondary contacts characterized by stationary and movable secondary contacts, one of which stationary and movable contacts is retractably mounted on a drawout circuit breaker, the other of which stationary and movable secondary contact is mounted on a cell into which the drawout circuit breaker is movable, one of the movable and fixed secondary contacts being retractably mounted to enable closing of the stationary and movable secondary contacts before closing of primary terminal means and after opening of the primary terminal means, whereby remote breaker operations, such as metering, may be tested prior to closing of the primary contact means.

Secondary contacts for drawout switchgear

An oil filled distribution transformer having a secondary circuit breaker utilizing a cantilevered stationary contact which is engaged by a movable contact for completing a series circuit therethrough. The cantilevered exposed stationary contact, which is surrounded by insulating oil, allows the oil in the transformer to rapidly return to the contact area after circuit interruption providing for faster arc extinction. The movable contact can be a bridging contact which forms a circuit between the cantilevered stationary contact and a second stationary contact mounted above a support base. The movable bridging contact is spring biased toward an open position separated from the stationary contact, but with the circuit breaker in the normally closed position is held in engagement with the stationary contact by a latching mechanism which is responsive to a bimetal or magnetic trip to allow the circuit breaker to trip open during overload conditions. The front cantilevered contact is completely surrounded by oil. During circuit interruption the oil in the contact area vaporizes forming an arc bubble of gas. Exposing the contact to allow free flow of oil into the area of the arc bubble allows for faster arc extinction and circuit interruption under fault conditions.

Distribution transformer secondary circuit breaker having cantilevered

A circuit interrupter having a magnetic trip element which is integral with the latch. The disclosed circuit interrupter is provided with a bimetal and a magnetic trip element directly connected to the latch of the circuit interrupter which is drawn towards the bimetal, unlatching the circuit interrupter when current flow therethrough exceeds a high overload level. The disclosed circuit interrupter is particularly adaptable for use on a distribution transformer. A movable bridging contact for completing a series circuit between two stationary contacts is provided. The movable bridging contact is spring biased towards an open position separated from the stationary contacts, but with the circuit interrupter in the normally closed position is held in engagement with the stationary contacts by a latching mechanism which is responsive to the bimetal or magnetic trip element to allow the circuit breaker to trip open during overload conditions. The magnetic trip element is formed integral with the latching mechanism to reduce time delay before operation. A plurality of poles are operated using only one operating mechanism by connecting the elongated operating arms with a strong metallic member for simultaneous operation of all poles. The bridging contact is disposed near the end of an elongated operating arm which is linked to the circuit breaker operating mechanism. Each pole of the circuit interrupter is provided with a bimetallic trip element. The magnetic trip element can be formed from a single piece having a plurality of legs each disposed in proximity with the bimetal of one pole.

Integral magnetic trip and latch for a circuit interrupter

A distribution transformer having a secondary circuit breaker utilizing a movable bridging contact between two stationary contacts for completing a series circuit therethrough. The movable bridging contact is spring biased towards an open position separated from the stationary contacts, but with the circuit breaker in the normally closed position is held in engagement with the stationary contacts by a latching mechanism which is responsive to a bimetal or magnetic trip element to allow the circuit breaker to trip open during overload conditions. The conducting bridging contact completes a series circuit through the circuit breaker which opens during circuit interruption. The secondary circuit breaker can also, if desired, be provided with a signal-light circuit which activates a signal light, on the exterior housing of the transformer, when current through the circuit breaker exceeds a low signal overload value which is less than the trip value. The signal light circuit is reset by turning the operator handle, which is located on the transformer housing, past the on position away from the off position. An emergency overload control is provided for increasing the tripping level of the circuit breaker during selected overload periods. The bridging contact is disposed near the end of an elongated operating arm which is linked to the circuit breaker operating mechanism. A plurality of poles are operated utilizing only one operating mechanism by connecting the elongated operating arms with a strong metallic member for simultaneous operation of all poles. The single signal light provided for each multi-pole circuit breaker can be activated by the bimetals of any one of the individual poles.

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Bethel Park, PA, United States of America

Jack G Hanks