GB1407067A - Circuit breakers - Google Patents

Abstract

1407067 Automatic circuit-breakers LEGRAND SA 30 Nov 1972 [2 Dec 1971 21 March 1972 5 July 1972] 55423/72 Heading H1N An automatic circuit-breaker has a pivotally mounted operating handle 50 which provides a cam surface, e.g. in a slot 72, a coupling member 52 slidable in slots in the housing 10 and urged into engagement with the cam surface, a tripping lever 51 which is centrally pivoted, at 63, to the movable contact 40 of the circuit-breaker and has at one end a notch which co-operates with the member 52, and a tripping device which acts on the other end of the lever 51. As shown the tripping device comprises an electromagnet 18 with a core 26 carrying an abutment 66 which moves the lever 51 to release the notch from coupling member 52 so that a spring 49 can open the contacts 40, 15. The abutment 66 may also strike the contact 40 when the core is attracted to assist in opening the contacts. The notch may be released from the member 52 by a slidable member 59 which is operated by a bimetallic strip 17. When the circuit-breaker is tripped a spring 54 returns the handle 50 to the off position so that the lower edge of the slot 72 cams the member 52 along the slots in the housing to a position where the notch on the tripping lever 51 re-engages the member to reset the mechanism. The circuit-breaker has an arc-extinction chamber 16 with deionizing plates 20 and outer metallic members 30, 31 connected by tongues 32 to the adjacent plates 20 so that passages in which arcs will not form extend between the region of the contacts and vents 35. The movable contact 40 is pivoted in slots 42 inclined such that the spring 49 provides sliding contact with fixed contact 15.