Abstract: A current limiting power switch has a monolithic stationary conductor with a conductor section that mounts fixed contacts that engage moving contacts on moving contact fingers to form a reverse current loop with the contacts closed. A terminal section projects transversely from one end of the conductor section and an arc runner section extends from the other end. The tapered arc runner has a generally laterally centered tapered area that gathers the arcs and urges them along a raised rib on the arc runner to an arc chute. A reinforcing rib running from the back of the conductor and arc runner sections to the terminal section resists distortion of the monolithic stationary conductor by the high temperatures and closing and electromagnetic forces during interruption.

Abstract: A moving contact assembly for a high-current interruption electric power switching apparatus has an inner carrier for the contact fingers that is rigidly held in a withstand position in an outer carrier by a spring biased cam follower pin engaging a cam profile on the inner carrier and configured to positively seat an inner carrier stop against an outer carrier stop on the outer carrier and to rapidly drive the inner carrier to a blow open position in response to a fault. The cam profile has an extended width divided between spaced apart cam profile sections to absorb the high closing and withstand forces. An abutment on the outer carrier resists bowing of the cam follower pin between the cam profile sections. Complementary convex and concave partial cylindrical surfaces on the inner carrier and a gas shield on the moving assembly carrier body maintain an arc gas seal during blow open.

Abstract: A moving contact assembly for a high-current interruption electric power switching apparatus has an inner carrier for the contact fingers that is rigidly held in a withstand position in an outer carrier by a spring biased cam follower pin engaging a cam profile on the inner carrier and configured to positively seat an inner carrier stop against an outer carrier stop on the outer carrier and to rapidly drive the inner carrier to a blow open position in response to a fault. The cam profile has an extended width divided between spaced apart cam profile sections to absorb the high closing and withstand forces. An abutment on the outer carrier resists bowing of the cam follower pin between the cam profile sections. Complementary convex and concave partial cylindrical surfaces on the inner carrier and a gas shield on the moving assembly carrier body maintain an arc gas seal during blow open.

Abstract: A shorting switch eliminates arcing faults in power distribution equipment. The shorting switch includes an insulating tubular housing; a first contact; a second contact; and an insulator between the first and second contacts in the insulating housing. The insulator prevents electrical connection of the first and second contacts. First and second terminals are respectively electrically connected to the first and second contacts. A wave spring mechanism moves the first and second contacts toward closure. A slug and an activated charge mechanism drive the insulator from between the first and second contacts, in order to electrically connect the first and second contacts.

Abstract: A shorting switch eliminates arcing faults in power distribution equipment. The shorting switch includes an insulating tubular housing; a first contact; a second contact; and an insulator between the first and second contacts in the insulating housing. The insulator prevents electrical connection of the first and second contacts. First and second terminals are respectively electrically connected to the first and second contacts. A wave spring mechanism moves the first and second contacts toward closure. A slug and an activated charge mechanism drive the insulator from between the first and second contacts, in order to electrically connect the first and second contacts.

Abstract: A current throttle resistor external to a contactor device protects an electrical power distribution circuit coupling a load to a power line. The contactor has electrical switching contacts in series with the load and the line, and for example, an electromagnetically controllable switch for opening the contacts. A current sensor is coupled to the controllable switch for opening of the contacts upon occurrence of a high current fault in the power distribution circuit exceeding a predetermined threshold. A resistive element in series with the power distribution circuit between the line and the load, provides a voltage drop for limiting current during the high current fault. The resistive element can be a nichrome strip or similar positive temperature coefficient resistance having a low cool resistance, and is thermally isolated from the controllable switch by mounting in a resistor housing external to the contactor.

Abstract: A molded case circuit breaker having current limiting capabilities optimized for relatively smaller frame sizes. More specifically, one aspect of the invention relates to a two-piece carrier assembly for carrying the main and arcing contact arms which allows the main and arcing contacts to be blown open during short circuit conditions. The two-piece carrier assembly includes an inner carrier and an outer carrier pivotally connected together. The contact arms are carried by the inner carrier. When sufficient magnetic repulsion forces are exerted on the contacts due to a short circuit condition, the inner carrier pivots relative to the outer carrier to allow the contact arms to blow open. In order to control the amount of force required for blow open, a compression spring loaded cam assembly is provided.

Abstract: A circuit breaker having a housing, fixed and movable contacts respectively supported by a fixed contact support structure and a movable contact arm, a trip mechanism, and an operating mechanism which is releasably engageable with the trip mechanism. The operating mechanism includes a pivotable operating member and a tension spring. The fixed contact support structure includes a contact supporting leg portion. The movable contact arm has a contact supporting side, and an opposite spring supporting side. The tension spring links the pivotable operating member and the spring supporting side of the movable contact arm. The contact supporting leg portion of the fixed contact support structure and the movable contact arm are disposed in closely spaced relation when the fixed and movable contacts are in engagement, to provide a reverse current loop which magnetically assists in rapid contact separation.

Abstract: A current limiting circuit breaker characterized by pairs of stationary and movable contacts with the movable contacts connected in series; an arc-extinguishing chamber including arc guide rails associated with each pair of contacts and in side-by-side relationship; manually operable means for opening and closing the circuit through the contacts; current-limiting electromagnetic means for opening the contact; and linkage means between the manually operable and electromagnetic means for enabling opening of the contacts by the electromagnetic means without tripping the manually operable means.

Abstract: A current limiting solenoid operated circuit breaker characterized by an arc quenching chamber having spaced arc guide rails along opposite sides of the chamber, stationary and movable contacts in an arcing zone adjacent to the chamber and electrically connected to corresponding guide rails, and a conductor around the arcing zone to generate a transverse magnetic field through an arc to drive the arc from the contacts and along the guide rails to the arc quenching chamber.