| 摘要 |
1,210,102. Automatic circuit breakers; electromagnetic switches. TERASAKI DENKI SANGYO K.K. 26 Jan., 1968 [27 Jan., 1967 (3)], No. 4181/68. Heading H1N. In a current limiting automatic circuit breaker the movable contact 14 and the normally fixed contact 16 are arranged to be moved in opposite directions by electrodynamic repulsion independently of the usual trip mechanism and held apart by individual overcentre springs 32, 60, the trip mechanism operating a short while later to move the contact 14 to its normal open position and to reset the contact 16 to its normal closed position. The contact 16 is mounted on a fixed pivot 44 and overcentre springs 60 act between a pin 56 on contact 16 and a pin 52 on links 46 freely pivoted on a fixed pivot 48. The contact 14 is pivoted at 22 to a carrier 24 itself mounted on a fixed pivot 26. The overcentre springs 32 act between pins 36, 40 on the contact and carrier respectively. The carrier is coupled by a conventional overcentre spring toggle linkage to a handle 82; the linkage being latched by a conventional trip unit 105 including a bimetal 108 and electromagnet 112. In the closed position springs 32, 60 provide contact pressure. On overload or excess current the mechanism acts conventionally to move the carrier 24 together with contact 14 to its open position (Fig. 4, not shown). Upon the occurence of a short circuit the electrodynamic forces between the parallel contacts 14, 16 are sufficient to throw the contact apart, the springs 32, 60 passing overcentre. Immediately after this the normal electromagnetic trip 112 releases the mechanism to move carrier 24 to the open position, contact 14 engaging a stop 28a to reset spring 32. An overhang 24b on carrier 24 engages a slide 76 freely movable in the housing; the other end of slide 76 drives the contact 16 back to its normal position. |
