GB1179910A - Fluid-blast circuit interrupters with improved electromagnetic driving means. - Google Patents

Abstract

1,179,910. Fluid blast switches; electromagnetically assisted switches. WESTINGHOUSE ELECTRIC CORP. 25 Jan., 1968 [16 Feb., 1967], No. 3994/68. Heading H1N. In a fluid blast switch of the " puffer" type the movement of piston 8 is assisted electromagnetically by a coil 33 in series with the arc 15 during interruption and co-operating with a fixed shorted coil 37. The piston 8 which moves in a fixed insulating cylinder 56 carries the movable contact 6 of the switch, an arcing electrode 31 insulated from contact 6 and an insulating nozzle 39. The coil 33 is connected between the electrode 31 and contact 6. During opening piston 8 is initially moved by a rod 17; the flow of fluid through openings 38 in piston 8 rapidly transfers the arc struck between separating contacts 5, 6 to the electrode 31 connecting the coil 33 in series. The coil 33 induces a current in the shorted turn 37 and is thus repelled by it, downwards, to assist the opening operation. A second fixed coil 52 may be arranged adjacent the shorted coil 37 and the current in coil 52 is arranged to flow also in a third coil 53; this in turn induces a current in disc 50 forming a floating piston which is thus repelled upwards to increase the flow of fluid. The assembly may be mounted in a tank filled with SF 6 at 60 p.s.i. In a modification (Figs. 8, 9, not shown), the cylinder is conducting and the upper part of its wall forms the shorted coil.