| 摘要 |
A switch mechanism opens a contact set (1,2) in the event of an undervoltage condition. The mechanism involves a lever assembly (3) biased by a spring (9) for pivoting about one or other of two fulcrums to open or close the contacts respectively. The undervoltage causes a solenoid (6) to release a plunger (7) which initiates operation about a fixed fulcrum (8). A reset device (10) is used manually to initiate operation about a movable fulcrum (4) provided that the voltage is sufficient. An arm (5) is deflected by the plunger to shift the movable fulcrum and also acts to restore the plunger during reset. The switch mechanism may be incorporated in a residual current device which provides the undervoltage condition on detecting an electrical fault. <IMAGE> |
