Circuit breaker with instantaneous trip provided by main conductor routed through magnetic circuit of electronic trip motor

摘要

The toggle mechanism (13) of a circuit breaker (1) is connected at one end to the pivoted contact arm (33) and at the other end to a pivoted latch lever (53) which is engaged to latch the toggle mechanism (13) by a latch member (85) pivoted for movement in a plane (107) perpendicular to the plane (105) of the toggle mechanism (13). The latch member (85) serves as an armature (93) for a trip motor (119) energized by a trip circuit (139) responsive to an arc fault and/or a ground fault to unlatch the toggle mechanism (13) and trip the circuit breaker (1) open. The latch member (85) is also tripped by a helical bimetal (109) responsive to persistent overcurrents and coupled to the latch member through an ambient compensator bimetal (113) cantilevered from the latch member (85). A flexible shunt (111) connected between the helical bimetal (109) and contact arm (33) passes through an extension (143) of the magnetic circuit (124) of the trip motor (119) to generate a magnetic field of sufficient strength to trip the latch member (85). A flexible shunt (111) connected between the helical bimetal (109) and contact arm (33) passes through an extension (143) of the magnetic circuit (124) of the trip motor (119) to generate a magnetic field of sufficient strength to trip the latch member (85) instantaneously in response to a short circuit.