GB796080A - Improvements in or relating to automatic electric circuit breakers - Google Patents

Abstract

796,080. Automatic circuit-breakers. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. May 30,1956 [June 9, 1955], No. 16677/56. Class 38 (5). [Also in Group XXXVI] A circuit-breaker with a time delay trip device, providing long and short delays, is arranged to trip instantaneously if a fault current flows during the closing operation. In a circuit-breaker generally similar to that described in Specification 789,056, magneticallyinsulated cores 166 and 167 are mounted horizontally and attract armatures 292 and 193 to respective pole faces 173 and 179. Armature 193, having the lower setting, is pivoted at 199 and operates the main time-lag device 245, which is similar to that of the abovementioned Specification, through a spring link 201 and member 211 secured to the diaphragm 227 of device 245. At the end of the delay, a pin 217 on the link 201 engages trip lever 225, also pivoted at 199, and raises it into engagement with trip-bar 125. Armature 292 has a higher setting and operates a valve, as in the above-mentioned Specification, to reduce the time lag of device 245. Armature 292 is carried on a lever 293 which is pivoted at 199, and has pivoted on it at 345 a spring-controlled lever 347 which is normally held inoperative by a lever 355, pivoted at 199 and carrying roller 359, coacting with switch arm 33. When the breaker is open lever 355 is moved clear and the end of lever 347 moves beneath a projection 349 on arm 225 and enables armature 292 to effect instantaneous tripping of the breaker if it is attracted during circuit closing. A compression spring 373 in a cylindrical cover 379 tends to cause the lever 355 and roller 359 to follow the switch arm 33 during closure of the breaker, but the dashpot action of a piston 371 in a cylinder 367 delays this movement, so that lever 355 does not free the lever 347 from projection 349 until after the breaker is fully closed.