GB950814A - Improvements in tripping mechanism for an electric circuit breaker - Google Patents

Abstract

950,814. Automatic circuit breakers. GENERAL ELECTRIC CO. May 21, 1962, No. 19455/62. Heading H2B. A stripping mechanism for a circuit-breaker includes an electromagnetic tripping device (Fig. 4) comprising an armature 68; a pivoted cam follower 74 limiting the de-energized position of the armature and a cam 81, rotatable to adjust the position of the follower 74 with respect to the armature and adjustable axially on its shaft 82. Each of three poles of a circuitbreaker comprises a movable contact 16 spring mounted 26 on a carrier 17, the carriers of all poles being rigidly linked by a bar 24. The centre carrier is operable through a toggle linkage 34, 36 and overcentre tension spring 41 by a handle 38. The toggle is supported by an arm 29 engaged by a latch 32 of the tripping mechanism which is assembled in a separate removable housing 20. Bimetal tripping elements 56 and electromagnetic tripping devices are associated with each pole of the breaker, each acting on a common trip bar 55 to release the latch 32 and open all the contacts. The action of the bimetal 56 is adjustable (Fig. 7 not shown) and is ambient temperature compensated by a second bimetal 60. In the electromagnetic tripping device the armature 68 is attached to a push rod 69 spring biased away from the core 66. The separation of the core and armature in the de-energized position and thus the current necessary to trip the breaker is adjustable through cam 81 by means of a knob 86. The maximum and minimum current values may be independently preset by adjusting a screw 78 and by moving the cam 81 along its shaft 82.