GB1016216A - Improvements in current-limiting circuit breakers - Google Patents

Abstract

1,016,216. Automatic circuit - breakers; switches, partly electromagnetic. GENERAL ELECTRIC CO. April 30, 1963 [May 18, 1962], No. 16880/63. Heading H2B. A circuit-breaker includes an electromagnetic current-limiting device operable in response to excess currents to move the normally stationary contact 18 (22) to open-circuit position prior to automatic opening of the main mechanism; the device comprising a magnetic core member 95(96) which attracts an armature member 97(98), attached to a pivoted contact arm 17 (23) carrying the normally stationary contact 18(22), under extremely high short-circuit conditions. The main contact carrier 20 is thermally tripped by a bimetal 82, adjustable by a screw 83, high current through the terminal strap 27 and a magnetic core 80 inducing currents in a copper loop 81 and heating of bimetal 82, which pushes a pivoted bar 84 to move a trip rod 67 and withdraw the latch 62 from the spring-biased contact carrier 20. More rapid tripping occurs when an armature portion 86 of pivoted bar 85 is attracted from pole extension 91 to pole extension 90 of the magnetic core 80 under short-circuit conditions, thereby moving the trip-rod 67. The spring-biased contact arms 17, 23, are latched open by latches 59, 50, after the electromagnetic actuation, until the breaker is reset manually. The breaker is operable manually via levers 101, 110, plunger 111 and lever 112 actuated through a roller member 35B on the support 35 of handle 34.