GB534863A - Improvements in or relating to electric circuit breakers with fluid-actuation - Google Patents

Abstract

534,863. Actuation of switches; oil-break switches. GENERAL ELECTRIC CO., Ltd., COATES, H. J., and GARRARD, C. C. Oct. 9, 1939, No. 27505. [Class 38 (v)] The tubular movable contact 10 is pneumatically actuated into and out of engagement with a fixed contact in an arc-control device 4 by means of piston 8 in a metal cylinder 7, which is located within a condenser or other terminal bushing 6 in an oil tank and has inlet openings 11, 12 for the compressed air. The piston rod 9 carries latches 22, 23 which are engageable with studs 24, 25, respectively at the ends of its stroke and releasable by the air-pressure acting on pistons 20, 21 in the main piston. The stud 25 and wiping contacts 16 are carried on a subsidiary cylinder 15 secured in the main cylinder and housing a piston-like enlargement 17 on the contact rod 10, the arrangement providing, during circuit opening, a stream of oil from the cylinder 15 through apertures 18 and contact 10 and preferably of a volume equal to that of the space vacated by contact 10. The compressed-air supply may be cut off by an auxiliary switch or after a timeinterval and prior to the end of the stroke, the latter being completed by the expansion of the air. The end of the closing stroke may be damped by a compressed spring between cylinders 15, 7 and other damping arrangements comprise the gradual closure of oil-orifices 19 by the descending piston and of orifices 18 by the collars 27 on cylinder 15 as the piston rises. The stud 24 is extended beyond the cylinder 7 to form a terminal 30. The switch may be adapted for horizontal mounting and be of withdrawable construction.