TW200515447A - Circuit breaker - Google Patents

Abstract

To improve breaking performance by preventing a movable contact from bouncing back from an open position with the use of a spring member having a pressure-receiving spring as a movable contact integrated in a contact holder. The circuit breaker has a rotational bridging type movable contact 4 loosely retained by a contact holder, and drives the movable contact toward the open position with electromagnetic repulsive force acting between fixed contacts 2, 3 and the movable contact when an overcurrent flows. Two sets of dual-torque springs 7 functioning as the pressure-receiving springs of the movable contacts are arranged at the contact holder is disposed in axially symmetrical positions with respect to a rotation center of the movable contact, and contact points of the movable contactor are pressed and pushed against the fixed contacts with a spring load of the spring member at a closed position. A load acting point of the movable contact of the dual-torque springs is set at a position in the vicinity of the closed position so as to make the movable contact push toward the closed position, and at a position in the vicinity of the open position so as to make the movable contact reversely push toward the open position along a reverse acting direction of the spring load.