General Electric Company

Eldon B Heft

Irvin C Huseby

Jan W Szymaszek

Keith W Klein

Joseph B Kelaita

Joseph Francis Johnson

A ceramic useful as an electrically insulating material is produced by calcinating wollastonite powder, admixing the calcined powder with phosphoric acid of certain P.sub.2 O.sub.5 concentration range, die-pressing the resulting mixture, and firing the resulting pressed piece. The ceramic is employed within arc circuit breakers as a substitute for asbestos liners, dividers and arc splitters.

Molding composition for arc circuit breakers

An electric circuit breaker includes an insulated latch and cradle mechanism to prevent deleterious arc formation between their points of separation when the circuit breaker contacts are opened under short circuit conditions. One embodiment employs an insulated latch mounted on the breaker armature.

Insulated latch-cradle mechanism

A thermal shield is employed with a circuit breaker operating spring to protect the spring from thermal degradation during contact arcing. One embodiment includes an ablative plastic coating on the outer surface of the shield to promote arc quenching.

Thermal shield for circuit breaker operating spring

A ceramic useful as an electrically insulating material is produced by calcining wollastonite powder, admixing the calcined powder with phosphoric acid of certain P.sub.2 O.sub.5 concentration range, die-pressing the resulting mixture, and firing the resulting pressed piece.

Molding composition and product produced therefrom

A rearward extension of a circuit breaker pivotally mounted movable contact arm is positioned, with the arm in its closed position, to engage a trip bar and trip the breaker in response to popping movement of the arm away from its closed position as induced by the flow of high level fault current. The trip bar is configured such that the circuit breaker is not tripped incident to manual operation of the movable arm between its open and closed positions.

Contact pop responsive latch release for circuit breakers

The common trip mechanism of a multi-pole circuit breaker is supplemented by individual breaker pole trip mechanisms operating independently of each other in response to fault current flowing in its breaker pole to unlatch the movable contact arm operating therein for uninhibited, independent opening movement from its closed circuit position to a tripped open position motivated by the electrodynamic forces associated with its breaker pole fault current.

Individual circuit breaker pole trip mechanism

A molded case circuit breaker of relatively narrow width is afforded dramatically increased current interrupting capacity by providing shielding against the electromagnetic field developed as the result of short circuits flowing through a contiguous circuit breaker. Additionally, an arc runner is added to cooperate with an improved arc chute construction in controlling to extinction the arc developed incident to an interruption. The case is also vented to relieve the internal gas pressure during arcing.

Molded case circuit breaker with improved interrupting capacity

A circuit breaker designed for automated assembly includes pairs of fixed and movable contacts, the latter carried by a carrier mounted for reciprocating movement in the breaker case. Operating and trip mechanism parts are mounted on a frame positioned in the case. A handle slideably mounted by the case actuates the operating mechanism to open and closed circuit positions. A fixture is utilized with the frame for calibrating the thermal trip setting and for partial assembly of the operating mechanism.

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West Hartford, CT, United States of America

Eldon B Heft