GB472721A - Improvements in or relating to electric circuit interrupters - Google Patents

Abstract

472,721. High - tension switches. WESTINGHOUSE ELECTRIC & MANUFACTURING CO. Sept. 15, 1936, No. 25134. Convention date, Sept. 26, 1935. [Class 38 (v)] A circuit-breaker is provided with means for rapidly producing simultaneously a plurality of short arcs on opening the circuit, and means for subsequently effecting a further total separation of the contacts to provide a sufficient gap to insulate effectively the disconnected circuit from the source of supply. The circuit-breaker shown is mounted in an oil tank 1 having a cover 3 supporting a pair of insulators 7 carrying the conductors 15 and the stationary contact assemblages 11. The circuit is completed through a movable bridging contact 13 connected to an operating rod 67, each of the contact assemblages 11 comprises four pairs of separable contacts 23, 33, each pair being mounted in an arc-extinguishing device 31 comprising a stack of slotted plates of insulating material with interposed iron plates which cause the arc to move longitudinally within the passage formed by the aligned slots. The various elements of each of the . stationary contact assemblages are mounted between a pair of insulating plates 19. The contacts 23 of each pair of movable contacts are X-shaped, and are mounted on pivots 25 supported by the plates 19, each contact being urged towards the associated arc-extinguishing structure 31 by a pair of springs 27. The contacts 33 of each pair are T-shaped, and are mounted on pivots 39 supported by the plates 19, each contact having an upturned end 35 adapted to pass through the slot in the arc extinguishing structure 31 and engage the associated contact 23. The contacts 33 are mechanically interconnected by a tie-rod 41 of insulating material, which extends through an opening in each contact and is pivoted to the contact at 45 or 46. The pivot pin 46 of the lowermost contact 33 is connected to a pair of springs 47 which bias the tie-rod to the open position. The bridging contact-member 13 carries a pair of upstanding contacts 71 which engage contacts 73 at the lower ends of each of the tie-rods, and move the latter to the closed position when the contact-member 13 is raised. The various pairs of contacts 23, 33 are connected in series by flexible shunts 63, the lowermost contact 33 being connected by a similar shunt to the contact 73. When the bridging member 13 moves downwards on opening the circuit, the springs 47 cause the rods 41 to follow the movement, producing a plurality of short arcs between each pair of contacts 23, 33, the arcs being lengthened at a speed much greater than the speed of the rods owing to the leverage. When the contacts 33 have reached the limit of their movement, subsequent movement of the bridging member 13 separates the contacts 71, 73.