Westinghouse Electric Corporation

Eaton Corporation

John G Salvati

Alfred E Maier

William E Beatty, Jr

Douglas Charles Marks

Louis N Ricci

Ronald W Crookston

James R Farley

Yun-Ko N Chien

Richard E White

Andrew James Male

Paul Skalka

Steven Castelein

Lawrence B St Clair

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. Another important aspect of the invention relates to a contact spring housing which relocates the contact springs away from the separable contacts to protect the springs from damage, for example, from heat due to contact separation. In order to improve the interruption time of the circuit breaker for relatively large overcurrents, such as a short circuit, a reverse current loop is provided which generates sufficient magnetic repulsion forces to blow open the separable contacts in a relatively short period of time. Within the restraints of the physical dimension of a relatively smaller breaker frame size, additional features have also been incorporated. More specifically, an improved rating plug assembly is provided with a one-piece plunger, relatively easier to manufacture than known designs which utilize two-piece plungers. Another aspect of the invention relates to an auxiliary cam plate for controlling the motion of the crossbar at the remote end in a four pole circuit breaker. The cam plate compensates for bending of the crossbar to improve the contact force in the remote pole. Lastly, a molded interphase barrier forms a gas barrier within the circuit breaker and maintains its position during assembly relatively better than known interphase barriers.

Molded case current limiting circuit breaker

A circuit interrupter trip unit characterized by a magnetic sensing and tripping device having improved means for adjusting between maximum and minimum air gaps between a magnet and armature for specific trip currents.

Circuit interrupter trip unit

A circuit breaker responsive to abnormal currents in conductors of an electrical distribution system characterized by separable contacts and trip means therefor, which means comprises a stationary magnetic structure for each conductor including a magnetic coil and core assembly and armature therefor, a lever associated with each stationary magnetic structure removing a trip bar to an unlatched position, the lever comprising the armature and being movable in response to abnormal currents in at least one of the conductors, and tension means for varying tension on the lever and including a manually operable cam, cam follower, and tension spring operatively connected between the cam follower and the lever for adjusting the force required to attract the armature to said assembly.

Circuit breaker

Each section of a three-phase metal enclosed switchgear unit is provided with main through horizontal bus and vertical section bus. The front of each switchgear section is divided into vertically disposed enclosures for housing circuit breakers or circuit interrupting devices. The circuit breakers are mounted close to the vertical section bus with the front of the circuit breaker and the circuit breaker operating handle recessed from the front of the switchgear section. Pan or well-shaped front covers, having a bottom surface flushed with the circuit breaker fit over the front of the vertically disposed enclosures and are mounted to the front of the switchgear section. Different depth wells or pans are used for the front cover, with the depth being determined by the circuit breaker physical size, which is dependent on the breaker rating. The surface of the well flush with the circuit breaker device has a cutout through which the circuit breaker operating handle projects. The front cover wells provide a dead front construction with easy access to the circuit breaker operating handles. A portion of the cover well approximately flushed with the front of the circuit breaker can have additional cutouts for showing breaker rating and providing easy access to external magnetic breaker adjustments.

Metal enclosed switchgear having well-shaped front covers

A molded case circuit breaker enclosed in a metal cabinet with an openable cover. An operating mechanism has a mounting plate secured to the face of the circuit breaker and a sliding plate movably supported on rollers by the mounting plate at the side of the circuit breaker. A handle mechanism is secured to the sliding plate with a portion extending through an aperture in the cabinet cover. A gasket is disposed between the handle mechanism and the interior of the cabinet cover. The handle mechanism is spring-loaded against the gasket and interior of the cabinet cover to provide a dust-tight seal.

Enclosed circuit interrupter including externally operable handle

Growing community of inventors

Beaver Falls, PA, United States of America

John G Salvati