Abstract: A cassette assembly for rotary contact circuit breakers utilizing a first electrically insulative cassette half piece and a second electrically insulative cassette half piece which are arranged to mate with each other to form an enclosure. The electrically insulative cassette half pieces include improper installation rejection features for both the rotor and arc chute assemblies. The inner surface of a electrically insulative cassette half piece including a groove and recesses formed therein. A rotor is properly positioned within the electrically insulative cassette half piece by inserting a pin on the face of the rotor into the groove. An arc chute assembly is properly positioned within the electrically insulative cassette half piece by inserting a tab located on a side member of the arc chute assembly into a corresponding recess located in the electrically insulative cassette half piece.

Abstract: A cassette assembly for rotary contact circuit breakers utilizing a first electrically insulative cassette half piece and a second electrically insulative cassette half piece which are arranged to mate with each other to form an enclosure. The electrically insulative cassette half pieces include improper installation rejection features for both the rotor and arc chute assemblies. The inner surface of a electrically insulative cassette half piece including a groove and recesses formed therein. A rotor is properly positioned within the electrically insulative cassette half piece by inserting a pin on the face of the rotor into the groove. An arc chute assembly is properly positioned within the electrically insulative cassette half piece by inserting a tab located on a side member of the arc chute assembly into a corresponding recess located in the electrically insulative cassette half piece.

Abstract: An arc runner is fixedly retained on a load (or line) strap without hardware and without employing a mechanical operation. Either the arc runner or the strap has features, such as legs or holes, which engage notches or pins on either the strap or the arc runner and cause the arc runner to be retained on the strap.

Abstract: A vent screen for a use in a circuit breaker cassette having structural characteristics that allows it to be assembled correctly within the circuit breaker cassette and where the vent screen allows for the flow of arc gases from the arc chambers.

Abstract: A rotor spring insulator assembly comprises a base member having a D-shaped opening therein and a connecting rod of a D-shaped cross section dimensioned to be received in the D-shaped opening of the base member. The flat edge of the D-shaped connecting rod faces a spring of a rotor thereby maximizing the distance and the amount of insulative material between the connecting rod and the spring to minimize the chance that arcing will occur between the connecting rod and the spring.

Abstract: A cassette assembly for rotary contact circuit breakers utilizing a first electrically insulative cassette half piece and a second electrically insulative cassette half piece which are arranged to mate with each other to form an enclosure. The electrically insulative cassette half pieces include improper installation rejection features for both the rotor and arc chute assemblies. The inner surface of a electrically insulative cassette half piece including a groove and recesses formed therein. A rotor is properly positioned within the electrically insulative cassette half piece by inserting a pin on the face of the rotor into the groove. An arc chute assembly is properly positioned within the electrically insulative cassette half piece by inserting a tab located on a side member of the arc chute assembly into a corresponding recess located in the electrically insulative cassette half piece.

Abstract: An electrically conducting strap for use in a rotary circuit breaker cassette provides dual connectors to accommodate either an electronic or mechanical trip unit within the circuit breaker and electrical distribution system. The continuous, integral strap includes a first section including a fixed contact mounted thereon, a U-shaped second section, a third section having two apertures for connection to associated electrical equipment, and a fourth section having two apertures for connection to a line of a distribution system providing electrical power to a load. Thus, the circuit breaker has the advantage of reduced cost and increased ease of manufacturability since a common cassette is used.

Abstract: A saddle assembly (10) for a circuit breaker comprising a saddle base (22), at least one stab terminal (14) and two resilient tabs (50, 52) in facing alignment for releasably securing the at least one stab terminal (14) to the saddle base (22), wherein the engagement of the two resilient tabs (50, 52) with the stab terminal (14) releasably secures the at least one stab terminal (14) to the saddle base (22).

Abstract: A rotary contact circuit breaker having a venting arrangement to vent gasses operated by a short circuit interruption to a location substantially above the load strap of the breaker whereby electrical components are not damaged by the gasses and ionized gasses from different phases are conveyed in discrete channels for a period exceeding the period during which ionization is present.

Abstract: The circuit breaker interlock arrangement of the invention utilizes a pair of detector assemblies, one mounted on the rear surface of each one of a pair of first and second adjoining circuit breakers and interconnected by means of an elongated rod. The operating mechanism tripping plunger rod in the first circuit breaker trips the associated first circuit breaker operating mechanism to open the first circuit breaker contacts when an attempt is made to close the first circuit breaker contacts when the second circuit breaker contacts in the second circuit breaker are already closed, and vice versa.

Abstract: Circuit breaker arc exhaust apertures in the line end of the circuit breaker case transfer arc gases from the circuit breaker interior during overcurrent circuit interruption. A flexible shield protects the circuit breaker terminal lug from arc gas contamination.

Abstract: An interlock arrangement between a pair of industrial rated circuit breakers in adjoining circuit breaker compartments utilizes a pair of circuit breaker interlock units, one mounted on the rear surface of each circuit breaker. A corresponding pair of compartment interlock units are arranged within the circuit breaker compartments for interaction between the two circuit breaker interlock units to open the contacts within one of the circuit breakers when an attempt is made to electrically connect the circuit breaker within one compartment when the circuit breaker in the adjoining compartment is already electrically connected within the adjoining compartment.

Abstract: Low voltage electric switchgear equipment includes a central processor unit electrically interconnected with electronic main and branch circuit interrupters within the same enclosure and used within a multi-phase power distribution circuit. A terminal connector block is connected by cable with each of the electronic trip units within the branch circuit interrupters to provide communications between the branch circuit interrupters and the main circuit interrupter for continuously updating the status of the branch circuit interrupters and their associated electrical equipment. Strain relief is provided to the cable connecting between the terminal connector block and the branch circuit interrupter to prevent damage to the electrical components within the electronic trip unit that are internally connected with the cable.

Abstract: An electronic trip molded case circuit breaker includes components that are designed for high speed robotic assembly. A unitary trip-to-test button is down-loaded within the circuit breaker housing for automatic alignment with the circuit breaker operating mechanism during the circuit breaker assembly process. A unitary auxiliary switch interface unit is also down-loaded within the housing for automatic alignment with the operating mechanism during the assembly process.

Abstract: A molded case circuit breaker having a pair of movable contact arms arranged within each pole of a multi-pole arrangement utilizes a shunt clip between the movable contact arms to insure electrical continuity between the contact arms and the contact arm support base. The movable contact arms and the support base are both accurately positioned within the circuit breaker case by means of an interference-fit between the outside edges of the support base and the interior sidewall surfaces of the circuit breaker case.

Abstract: An electronic trip molded case circuit breaker includes components that are designed for high speed robotic assembly. A unitary trip-to-test button is down-loaded within the circuit breaker housing for automatic alignment with the circuit breaker operating mechanism during the circuit breaker assembly process. A unitary auxiliary switch interface unit is also down-loaded within the housing for automatic alignment with the operating mechanism during the assembly process.

Abstract: An operating handle assembly for molded case circuit interrupters is robotically assembled to the circuit breaker operating mechanism without requiring any auxiliary fastening device. A visual access slot in the circuit breaker cover allows the condition of the circuit breaker contacts to be visually ascertained by use of colored indicia carried by the operating handle skirt. A slidably mounted handle shutter cooperates with the operating handle to prevent egress of arc exhaust gases in the event the circuit breaker contacts are closed or opened during overcurrent conditions when the circuit breaker is installed within an industrial power distribution circuit.

Abstract: A molded case circuit breaker of the type using electrodynamic repulsion to separate the circuit breaker contacts under intense overcurrent conditions also includes an arc chute arrangement for cooling and quenching the arc that occurs during such contact separation. A plastic cover insert added to the interior of the circuit breaker cover multi-functionally retains the arc chute within the circuit breaker case while providing clearance for the circuit breaker operating handle shutter. A resilient pad on the top surface of the cover insert receives the circuit breaker operating handle skirt upon contact separation and dampens the energy imparted to the operating handle and to the circuit breaker cover.

Abstract: A molded case circuit breaker having a pair of movable contact arms arranged within a single pole utilizes a shunt clip between the movable contact arms to insure electrical continuity between the contact arms and the support base during intense short circuit interruption. A compression spring-driven camming arrangement insures good electrical connection between the circuit breaker contacts under steady quiescent operating conditions while preventing reclosing of the contacts during short circuit interruption.