Westinghouse Electric Corporation

Robert H Hill

Alfred E Maier

John A Wafer

Joseph J Matsko

Paul Skalka

William I Stephenson, Jr

A current limiting circuit interrupter comprises a molded case, separable contacts disposed in the case, the contact arms supporting one of the contacts, an operating mechanism connected to the contact arm to move the arm between open and closed positions, and a slotted magnetic drive device generating electrodynamic force on the contact arm during extreme overcurrent conditions to rapidly separate the contacts. The magnetic drive device includes a molded housing forming a slot having insulated walls disposed about the contact arm, and a stack of U-shaped laminations of magnetic material fitted into the housing. The space between opposing walls of the housing is slightly less than the thickness of the lamination stack so that the laminations may be snugly press-fitted into the housing. The housing is then secured to the case in such a manner that the laminations are captured and securely positioned without the need for rivets or other fastening means extending through the lamination stack. The housing also includes molded recesses for receiving a compression spring to produce contact force when the contacts are in the closed position, and a molded stop member to limit the movement of the contact arm when the breaker is in the open position.

Current limiting circuit breaker with integral magnetic drive device

A circuit interrupter includes an interchangeable trip unit removably disposed in the circuit interrupter housing and connected between a current transformer and a trip mechanism. The trip unit contains electronic circuitry for activating the trip mechanism to open the contacts upon detection of overload current therethrough and includes rejection means provided to ensure that only a trip unit having circuitry compatible with the electrical characteristics of the circuit interrupter can be inserted into the housing. The rejection means comprise a plurality of pins mounted within the housing and extending into the recess to be occupied by the trip unit. The pins are arranged in a pattern unique to all circuit interrupters having identical electrical characteristics. A pattern of holes is provided in the enclosure of the trip unit, the hole pattern being unique to trip units having identical electrical characteristics. The pin pattern and hole pattern of compatible circuit interrupters and trip units, respectively, are identical, permitting such compatible trip units to receive all rejection pins of compatible circuit interrupters such that said compatible trip units can be completely inserted into the recess of the circuit interrupter housing. Interlock means are provided such that the circuit breaker mechanism is disposed in a trip free condition preventing closure of the contacts unless a trip unit is completely inserted into the circuit interrupter housing recess.

Circuit interrupter with interlocked interchangeable trip unit

A three pole molded case circuit breaker including a push-to-trip button, a flux transfer shunt trip mechanism, an undervoltage trip mechanism, and an improved latch mechanism. The latch mechanism comprises a metal trip bar covered with insulating tubing and adapted for translational movement to actuate the latch mechanism and trip the contacts. Contact carrier movement during the tripping operation serves to reset the latch mechanism.

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South Beaver Township, Beaver County, PA, United States of America

Robert H Hill