| 摘要 |
The outside poles (7a, 7b) of a three pole circuit breaker (1) are each provided with a blow open latch (87) which includes a latch hook (89) having an open slot (91) forming jaws (93) pivotally mounted on the contact arm (27). A torsion spring biases (101) the jaws (93) to a cocked position in which they are aligned for engagement with a fixed stop member (75) toward which the contact arm (27) rotates as it blows open in response to the magnetic repulsion forces generated by a short circuit. As the jaws (93) engage the stop member (75), the latch hook (89) is rotated to mechanically latch the latch hook (89) on the stop member (75) thereby preventing rebound and reclosing of the contacts (9). A leaf spring (103) mounted on the crossbar (53) holds the latch hook (89) in mechanical engagement with the stop member (75). As the circuit breaker (1) responds to the overcurrent condition and rotates the crossbar (53), the leaf spring (103) disengages from the latch hook (89) so that the torsion spring can rotate the latch hook (93) back to the cocked position for disengagement from the stop member (75) upon reclosing of the circuit breaker (1). <IMAGE> |
