IMPROVEMENTS IN AND RELATING TO ELECTROMAGNETIC ACTUATORS

摘要

An actuator for a circuit breaker includes a primary actuator mechanism for closing the circuit breaker contacts and resisting the closing, blow-open and contact pressure forces and a secondary actuator for providing or assisting in providing a fast acting opening of the contacts. The actuator includes a drive shaft for coupling to a movable contact of a circuit breaker, the primary actuator mechanism being adapted to propel the drive shaft between a first position and a second position, and the secondary actuator mechanism being adapted to, upon receiving a trigger signal, shorten the effective length of the drive shaft. In another configuration, the primary actuator mechanism drives a drive link from a first position to a second position during a closing stroke, the secondary actuator mechanism operates in concert with the primary actuator to drive the drive link from the second position to the first position during an opening stroke; the secondary actuator is reset by the primary actuator mechanism during a subsequent part of the opening stroke.