GB619243A - Improvements in or relating to electric fluid blast circuit breakers - Google Patents

Abstract

619,243. Fluid blast switches. ETABLISSEMENTS MERLIN & GERIN. Nov. 22, 1946, No. 34686. Convention date, Dec. 3, 1945. [Class 38 (v)] A fixed contact 1 co-operating with a plurality of spring-biassed contacts 2 pivoted on an annular conducting rib 8, carries at its lower end a spring clip contact 4 engageable by the isolating contact 5. Blast-fluid following a path F, F1 through ports 21 in a piston 6 carrying an insulating member 7, actuates the piston to open the contacts 2 against a cylindrical stop 12, and to release a radial blast of fluid which escapes through the hollow contact 1 and past arcing horns 14, such as those described in Specification 615,777, and through a muffler 15. A voltage-limiting impedance 16 is connected across the contacts. The movable contacts may alternatively be in the form of a pair of elongated members (Fig. 3, not shown), and may be pivoted on an insulating rib 8 and formed with a lug 18 (Fig. 5) so that the electrodynamic forces acting on the flexible connection 19 and the lug 18 counteract the contactopening forces due to the loop formed by the contacts 1, 2. To delay interruption until adequate blast pressure is built up, and then accelerate the contact opening, lost motion is provided between the member 7, and the contacts 2, for the first part of the piston travel, Fig. 5, and additional air supply ports 17 are uncovered by the piston as it reaches the useful part of its stroke.