GB542722A - Improvements in or relating to a.c.electric circuit-breakers of the gas-blast type - Google Patents

Abstract

542,722. Gas-blast switches. REYROLLE & CO., Ltd., A., AMER, D. F., and WEBB, W. H, June 17, 1940, Nos. 310/42 and 311/42 (divided out of 542,728). [Class 38 (v)] A gas-blast switch comprises a pair of arcing electrodes K, K' on which arcs are formed initially by separation therefrom of arc-initiating contacts H, H', the arcs being looped through insulating nozzles F, F' by blasts emerging therefrom and made to coalesce into a single arc. The blast-pressure also serves to move the contacts H, H' by acting on the pistons J, J' the contacts and associated parts being arranged generally as in Specification 542,728. A metal casing L<SP>1</SP> with insulating liner L has cooling and silencing units L<SP>2</SP> for the exhaust gases, and an insulated contact K<SP>4</SP> is separable from contact K<SP>3</SP> provide an isolating gap. In Fig. 2 two separate arcs are produced at upper and lower breaks, the contacts being arranged differently at the two breaks. In each break the movable contact at which the arc is initiated comprises a set of spring-pressed members O arranged on a spring piston O<SP>1</SP> which is moved by the blast pressure. One fixed arcing contact M<SP>2</SP> in each break comprises a bar passing through the nozzle M into engagement with a metal ring M connected to a metal casing N on a supporting insulator N'. The combined arcing and arc-initiating contact Q of the upper break is a solid member, whereas in the lower break, it may be tubular, but, as shown, there are separate arc-initiating and arcing contacts the former P being tubular and supporting by webs a rod-like arcing contact P<SP>4</SP>. A discharge casing N<SP>2</SP> is provided, as also a series, of conduits N<SP>3</SP> for conveying the blast gas to the upper break. In a further form, the spring contact members may be fixed and the movable arc-initiating contact may be tubular and move in the opposite direction to the blast, and arranged to surround the rodlike other fixed arcing contact electrically connected to it. The Specification refers also to a nozzle of conductive material insulated from the contacts.