GB563641A - Improvements in or relating to pneumatically actuated electric circuit interrupters - Google Patents

Abstract

563,641. Air-break switches ; actuation of switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Feb. 18, 1943, No. 2738. Convention date, Feb. 18, 1942. [Class 38 (v)] A circuit interrupter comprising arcing contacts in series with disconnect contacts and suitable for H.T. power circuits, have a pneumatic motor for each break and pneumatic interlock means for ensuring correct sequence of operation whereby the disconnect contact moves last both in opening and closing, so avoiding the need for a gas blast in circuitmaking in the case where such is employed for are-quenching. The arcing contacts, which may be as in Specification 553,714, are housed in a casing 23 and the movable contact 31 is operated by a motor in casing 19. The movable disconnect contact 39 is reciprocable by a motor also in casing 19 which is mounted on insulators on a frame 11 housing the compressed-air reservoir 67, blastvalve casing 73 for the arcing contacts, and closing and opening valves and valve-control mechanism, Figs. 4, 5 (not shown). The contact 39 is operated by a double-acting piston 105 in a cylinder 103 to which fluid is admitted through pipes 175, 183 communicating, respectively, with passages 171, 181 which are exposed to the fluid-supply only when the double-acting piston 101 to which contact 31 is attached, has moved a given distance of its operating stroke. The supply from the closing and opening valves is taken up the insulators 15, 17, pipes 125, 117 to passages 123, 115, respectively, in cylinder 99, this air also operating pistons 191, 201 to open valves 187, 197 to exhaust the opposite sides of the two pistons 101, 105 to atmosphere. The blast-valve solenoid is energized simultaneously with the opening-valve solenoid, and the opening valve is arranged to take precedence over the closing valve in the event that closure on to a faulty circuit occurs or that conflicting control impulses are impressed on the valve-solenoids. The control is effected in dependence on the movement of the disconnect contact 39, for which purpose a crank 273, Fig. 2, and linkage 271, 269, 267 operates auxiliary switch means 265, individual contacts of which are shown in Fig. 7 at 305, 330, 331, 341, together with blast-valve solenoid 93, solenoid 227 of opening valve 163, solenoid 251 of closing valve 165, reclosing relay 299, which may be automatic, protective relay 335, closing relay 283, release relay 289, and opening relay 325 energized by relay 335. Push-buttons 295, 343 are also provided for closing and opening, respectively. In operation, relay 335 energizes relay 325 which operates the blast and opening valves to open contacts 31, 39 in sequence, the movement of 39 at once closing the blast valve and, when terminated opening contacts 341 to de-energize relay 325 and opening-valve solenoid 227. If reclose relay 299 is energized by opening of contact 39, its contacts 301 energize relay 283 which in turn energizes solenoid 251 to initiate reclosure of 31, 39 in that order, whereupon contacts 205 close and energize relay 283 to de-energize relay 283 which in turn, at contacts 311, de-energizes relay 289 and, at contacts 281, the solenoid 251. The number of reclosures on to a faulty circuit may be limited by known means. A spring may return the contact 31 to closed position when the opening-fluid supply is cut off, Fig. 8 (not shown). Specifications 563,642 and 563,646 also are referred to.