MOLDED CASE CIRCUIT BREAKER AND MOVING CONDUCTOR ASSEMBLY THEREFOR

摘要

A molded case circuit breaker has a moving conductor assembly which includes a modular carrier assembly incorporating a plurality of spring biased contact ca m members each of which engages contact pressure lobes on a pair of contact arm laminations to provide contact pressure. In response to the magnetic repulsion f orces generated by a short circuit, the springs compress allowing the cam members to p ivot and side step the contact pressure lobes so that the contact arm blows-open with little resistance. The cam members and springs are preassembled in a transverse channel in the carrier body and laterally retained in place by side plates for easier pi votal attachment of the contact arm laminations to the lobes on the side plates. The s ide plate lobes raise the contact arm relative to the mass of the carrier to reduce eddy current heating and provide a positive off indication for welded contacts by res tricting movement of lower toggle links of the operating mechanism which are coplanar wit h the side plates. A modular crossbar includes molded bearings engaged by or made integral with hexagonal metal shaft sections which extend into hex openings in t he carrier bodies of adjacent poles.