Electromagnetic operating mechanism for HV circuit breaker - has flange on operating rod moving axially between close and trip coils

摘要

The HV circuit breakers has improved operating times esp. reduced opening time. The operating rod (1) ends in an actuator housing (2) containing close (4) and trip (3) coils at opposite ends. The operating rod has a flange (5) forming a secondary coil. The latch mechanism comprises moving (7) and stationary (6) cones and a cage (10) of balls (9). The cones give a wedge action against the balls in the switch closed position. The cage (10) forms part of an additional secondary coil (11). To open the circuit breaker, the trip coil (3), lying between the two secondaries (5, 11), is energised. The secondaries move apart and the upper one (11) lifts the cage and releases the latch. The lower one drives the rod to the open position. By arranging the secondary inductances, for example by suitable choice of metals of which the secondaries are constructed, peak thrust for unlatching is reached before peak opening thrust.