Abstract: A self-contained current limiter unit allows lower short-circuit-rated circuit breakers to be utilized within industrial applications. The unit is electrically-connected in series with the circuit breakers and the protected load to limit the short circuit current to a fixed predetermined value while the circuit breaker trip unit responds to interrupt the circuit current. A single unit can be arranged in electrical series connection with a plurality of lower short-circuit-rated circuit breakers to allow a substantial savings in component and equipment costs.

Abstract: A molded case circuit breaker having a thermal-magnetic trip unit is provided with a mechanical rating plug to allow a number of circuit breakers of different ampere ratings to be used within a common-sized enclosure. Multiple mechanical rating plugs are stored at the place of distribution to adapt the common enclosure to a specific ampere rating at a substantial savings in time, labor and materials.

Abstract: A molded case circuit breaker controlled by an electronic trip unit is cost-competitive with electromagnetic circuit interruption devices. A novel contact arm assembly and shield arrangement in combination with a contact arm spacer and operating cradle interface reduces the assembly time and the number of operating components to effect significant cost savings.

Abstract: A molded case circuit breaker having a thermal-magnetic trip unit is provided with a mechanical rating plug to allow a number of circuit breakers of different ampere ratings to be used within a common-sized enclosure. The rating plug interacts with a thermal-magnetic trip unit to set the circuit breaker ampere rating.

Abstract: A molded case circuit breaker controlled by an electronic trip unit is cost-competitive with electromagnetic circuit interruption devices. A novel contact arm assembly and shield arrangement in combination with a contact arm spacer and operating cradle interface reduces the assembly time and the number of operating components to effect significant cost savings.

Abstract: A system for remote control of a mobile computer system from a base computer system, where the base system generates control command tokens which are broadcast over a pager system. A communicator including a pager receiver, which is normally in a standby state, is connected to the mobile computer, which is normally in an off state, and receives the command tokens. Stored in both the base computer and the mobile computer is a table of commands, cross-referenced with the command tokens. The command tokens are used to instruct the mobile computer to take a variety of actions, including telephoning the base computer, informing the base computer of the mobile computer's location, exchanging file update information and application version information, and other actions requiring communication between the base station and the remote station. The communicator includes a local CPU and SRAM, and powers up the mobile computer as necessary.

Abstract: A molded case circuit breaker modular line strap assembly allows three components to be selectively interconnected for the different circuit breaker ampere ratings. A single component being used with the lower ampere ratings with additional components being additively assembled to accommodate the increased ampacity requirements with the higher ampere ratings.

Abstract: A molded case circuit breaker movable contact arm electrically connects with the circuit breaker load terminal by means of parallel electric paths provided by a looped braid conductor. The contact arm support includes a single support leg for pivotally retaining the movable contact arm on one side. The opposite side of the contact arm is supported on the operating mechanism crossbar. Contact arms of increasing thickness are used to accommodate the higher transport currents required with circuit breakers of increased ampere ratings.

Abstract: A compact molded case circuit breaker operating mechanism crossbar assembly allows a unitary crossbar design to be used within a wide range of circuit breaker ampere ratings. A common phenolic crossbar and a metal staple are used for the higher ratings. An L-shaped filler in combination with the crossbar and staple are used to adapt the crossbar to the staple for the lower ratings.

Abstract: A modular crossbar arrangement for molded case circuit breakers allows a plurality of contact arm assemblies to be interconnected from a single modular unit. To provide increased acceleration to the movable contact arms a contact arm accelerator lever interfaces with the contact arm and crossbar assembly. To promote further acceleration of the movable contact arms to their closed positions, the movable contact arms in a multi-pole circuit breaker are staggered with respect to their rotational alignment within each pole on the crossbar assembly.

Abstract: A modular crossbar arrangement for molded case circuit breakers allows a plurality of contact arm assemblies to be interconnected from a single modular unit. To provide increased acceleration to the movable contact arms a contact arm accelerator lever interfaces with the contact arm and crossbar assembly. To promote further acceleration of the movable contact arms to their closed positions, the movable contact arms in a multi-pole circuit breaker are staggered with respect to their rotational alignment within each pole on the crossbar assembly.

Abstract: A screw retainer is fabricated from a thin sheet of spring steel and is comprised of three sections: a screw support section, a leg support section and a leg section. The screw support section contains a through-hole for receiving a support screw. The leg support section is bounded by the screw-support section and the leg section. The leg section is angulated with respect to the leg support section and has a degree of spring action that allows it to be compressed so as to allow it and the leg support section to be inserted between the respective lower portions of integrally-formed upstanding support arms of a support base. Once the screw retainer is completely inserted between the respective lower portions of the integrally-formed upstanding support arms, the leg section springs back to its normal position thereby preventing the screw retainer from becoming dislodged from its position.

Abstract: A modular crossbar arrangement for molded case circuit breakers allows a plurality of contact arm assemblies to be interconnected from a single modular unit. To provide increased acceleration to the movable contact arms a contact arm accelerator lever interfaces with the contact arm and crossbar assembly. To promote further acceleration of the movable contact arms to their closed positions, the movable contact arms in a multi-pole circuit breaker are staggered with respect to their rotational alignment within each pole on the crossbar assembly.

Abstract: A multi-pole circuit breaker is formed from a modular array of single-pole circuit breakers. The individual circuit breaker operating handles are ganged together by means of a handle connector placed over the individual circuit breaker operating handles. The handle connector has a U-shaped central part flanked by a pair of C-shaped parts disposed on the outside portions thereof to facilitate switching the individual operating handles in unison.

Abstract: Field-installable accessories are used within a thermal-magnetic industrial-rated circuit breaker. One such accessory in the form of a combined undervoltage release and shunt trip unit is field-installable within the circuit breaker cover. A bell alarm accessory unit can also be inserted within the circuit breaker cover either in combination with or apart from the undervoltage-shunt trip accessory unit.

Abstract: A refractory fiber insert within the cover of a molded case circuit breaker interfaces between the interior of the circuit breaker cover and the top surface of the circuit breaker arc chute to prevent the arc by-products generated within the arc chamber from re-entering the arc chamber. A shaped slot formed within the fiber insert automatically compensates for manufacturing tolerances to precisely locate the insert between the cover interior and the top surface of the arc chute.

Abstract: A molded case circuit breaker utilizes a thermally responsive trip unit for providing long and short-time overcurrent protection and a magnetically responsive trip unit for instantaneous or short-circuit protection. An electrically and thermally insulative lever interfaces between the thermal element and the circuit breaker trip response bar to linearize the movement of the thermal trip element in response to circuit current.

Abstract: A molded case circuit breaker of the type containing an electronic trip unit and a combined actuator-accessory unit to articulate the circuit breaker operating mechanism employs an optimum cradle configuration within the circuit breaker operating mechanism. The operating cradle is fabricated from a steel composition that is optimized to promote improved hardness properties. The optimized cradle interacts with the circuit breaker latch assembly to substantially reduce the tripping force required to articulate the operating mechanism.

Abstract: A trip accelerator interfaces the thermal-magnetic trip unit and the operating mechanism within a thermal-magnetic molded case circuit breaker for improved response to overcurrent conditions within an associated electrical distribution circuit. The trip accelerator is in the form of a trip lever rotatably mounted on the operating mechanism side frame and is reset by the operating mechanism upon displacement of the circuit breaker operating handle.

Abstract: Field-installable accessories are used within a thermal-magnetic industrial-rated circuit breaker. On such accessory in the form of a combined undervoltage release and shunt trip unit is field-installable within the circuit breaker cover. A bell alarm accessory unit can also be inserted within the circuit breaker cover either in combination with or apart from the undervoltage-shunt trip accessory unit.