GB813734A - Improvements in or relating to electric circuit breakers - Google Patents

Abstract

813,734. Contact members for switches, arc-rupturing in switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. July 24, 1957 [July 31, 1956], No. 23415/57. Class 38 (5). A circuit-breaker with main, intermediate, and arcing, contacts which separate in that order, has a fixed contact base 41 with three supporting projections 45, 47, 49 carrying the resiliently-mounted fixed contacts. Two plates 39 carry main fixed contacts 57 and one pivoted on a spindle 51 and retained by a spindle 53 both having springs 63 urging the plates 53 against the projections 45, 49. L-shaped members 61 carrying main fixed contacts 59 are mounted in the same manner on spindles 51, 53 and coaxial springs 67 urge spacers 69 against the members 61 to ensure good contact with the inner projection 47, silver or similar good conducting material washers 71 and plating 73 on the projection being provided to improve the conductivity. The plates 39 are each biased toward the moving contacts by a spring 79 with one end on a pin 83 and the other in a recess 81. The members 61 are biased by coaxial springs 85 with one end in a recess 87 and the other on a pressure-equalizing member 91. The intermediate fixed contact 31 and arcing contact 33 are mounted on a member 35 having pivot pins 97 movable in slots 99 in the plates 39 and stops 101 in apertures 103 thereof. Coaxial springs 105 and a spring 107 urges the member 35 away from the base 41 and a flexible conductor 113 electrically connects these members. When the arm 15 is operated to open the contacts the fixed contacts move with the moving contacts until the spindle 53 engages the sides of the holes 75, 77 in the projections 45, 47, 49 (Fig. 4) and then the main contacts 23, 57, 59 separate. The other contacts remain closed until the pins 97 engage the ends of the slots 99 (Fig. 1) and then the intermediate contacts 25, 31 separate leaving the arcing contacts 27, 33 closed until the stops 101 engage the ends of the holes 103. An arc-shoot 127 is provided and an insulator 129 on the bar 15 prevents Bash-over to the fixed contacts on switching surges.