GB743787A - Improvements in or relating to high voltage electrical apparatus - Google Patents

Abstract

743,787. Fluid blast circuit-breakers. REYROLLE & CO., Ltd., A. March 15, 1954 [Dec. 17, 1952], No. 32007/52. Class 38(5) A switching impedance J for a fluid-blast circuit-breaker is mounted on a frame J' carried by a stress ring L, and is connected to an arcing contact E' by a conical structure K of perforated metal or rods generating a cone. The free end of impedance J is connected to one wall of chamber A and then through a spider M' to a probe electrode M normally engaged by moving contact G and situated in an exhaust chamber C containing an exhaust valve H of the type shown in Specification 736,088. When the circuit-breaker is closed, chamber A is at the same potential as the contact E, and when the circuit-breaker opens, the movement of contact G, initiates an arc which is drawn through an insulating or insulated metal nozzle B and then extinguished by gas blast, the resistance J being in parallel with the arc. On further movement of contact G a restriking arc is initiated between it and probe M which arc is, however, of small energy due to impedence J in series with it, and can then be easily extinguished. Arcing contact F carries a stress shield F<SP>1</SP>. In another embodiment (Fig. 2, not shown) the free end of the impedance is connected to a rod electrode passing through a metal nozzle which is connected to the uninsulated downstream arcing contact, the movable contact being housed in the wall of the chamber A and movable laterally into contact with electrode E. In yet another embodiment (Fig. 3, not shown) the resistance arc is formed in uncontaminated gas by connecting the impedance J to an annular probe electrode on the upstream side of the nozzle, the movable contact G passing with clearance through the probe electrode and the restriking arc extending between it and the probe in clean gas passing through a metal or insulating nozzle.