GB643808A - Improvements in or relating to fluid blast electric circuit interrupters - Google Patents

Abstract

643,808. Fluid-blast switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. March 11, 1948, No. 7462. Convention date, April 16, 1947. Addition to 600,733. [Class 38(v)] The fluid-blast circuit-breaker of the parent Specification is modified in that the time delay in the operation of the auxiliary fluid-blast producing device is produced by the valve action of movable contacts 9, 45, in orifices 148, 147, respectively. When the conducting bridging member 7 is moved downwards, the operating rod 22, which is screwed to the member 51 bearing on the member 7, moves down under the action of springs 67 to move contact 45 downwards. Owing, however, to a lost. motion connection between the rod 22 and the contact 9, the latter is initially moved downwardly by springs 36 to maintain engagement between contacts 9, 44 until the lower end of a sleeve 30, rigid with the rod 22, engages the head 33 of a pin 32 to which is pivoted a lever 15 forming part of a parallel-motion linkage 12-18, connected to the contact 9. A second parallel-motion linkage 52-55 and 57 interconnects the member 51 and the contact 45, there being a lost-motion between a pin 61 on the linkage and a slot 84 in a sleeve 83 integral with the piston 81, which moves down under the action of springs 89 and then only when interrupting low currents. The blast passes from the piston chamber 82 to a chamber 96 through orifices 95, and then upwardly in passages 117 and radially inwards to the pressuregenerating arc 63 through inlets 116. It then passes through orifices 147 and vents 125 into passages 126, and so to the interrupting arc 48 through inlets 131, exhausting through orifices 148 and vents 137. The piston chamber 82 is provided with a normally-open valve 106 which closes on downward movement of the piston, the time taken to close the valve also providing a delay. Alternatively, a lost-motion between the contact 45 and the piston may be provided, Fig. 10, (not shown), in which case the valve 106 is normally-closed.