GB1222456A - A current-limiting circuit breaker - Google Patents

Abstract

1,222,456. Automatic circuit breakers; electrodyriamically operated switches. MERLIN GERIN. 4 July, 1969 [5 July, 1968], No. 33723/69. Heading HlN. A circuit breaker comprises a movable contact arm 10, Fig. 4, connected by a current loop 16 and pivoted at 28 to a fixed support 30, 46 held by a pivoted actuator 34, 36 or latch 48, 50 whereby the electrodynamic forces in the loop 16 at first assist spring 33, and increase the pressure at contacts 18, 22 until the arcing contacts 20, 24 engage. After release of the latch 48, 50 due to electrodynamic forces in loop 16, support 30, 46 pivots freely at 32 whereby the electrodynamic forces in loop 16 assist spring 33 to force the contacts 18, 22 open. Electrodynamic release is obtained as a result of forces in the loop 16 which at first urges the latch rollers 48, 50 downwards against the action of a compression spring 64 tending to urge pivot 39 of arm 54 upwards by urging an elongation of linkage 60, 62. After limited movement, stop 70 of arm 54 positively engages extension 66 of link 62 whereby roller 50 is released from roller 48. This arrangement provides for a limited rise in current through loop 62 whereby roller 50 begins to move but can be returned to its initial locked position by the spring 64 if the current falls. A number of similar circuit-breakers may be linked through shaft 34 for simultaneous manual or an unspecified tripping operator or electrodynamic release. Manual or latch release of shaft 34 rotates the circuit breakers to the open position (Fig. 8, not shown) by lowering pivot 39 and roller 50 to release the support 30, 46 without release of the associated latch roller 50 from roller 48. In a modification the latch system comprises a spring-pressed plunger 92, Fig. 16, in a recessed housing 78. Electrodynamic forces in loop 16 or movement of actuator 34 causes plunger 92 to tilt out of recess 78 into recess 80 whereby pivot 28 and support 30 are released to move clockwise about pivot 32 and allow the contacts 18-24 to open under action of the spring 33 assisted by the electrodynamic forces in loop 16.