GB1038717A - High-voltage electric circuit breakers - Google Patents

Abstract

1,038,717. Fluid blast switches. E. MARX. July 12, 1963 [July 16, 1962; May 4, 1963], No. 27730/63. Heading H2B. A high voltage D.C., oil immersed circuit breaker comprises a pair of spring urged contacts 3, 4 and an insulating plate 11 movable between the contacts to separate them and to extend the arc thus formed between them into an oil filled chamber 7. The plate 11 is moved in guides 12 by the detonation of an explosive charge 19 which drives upwards a piston 18 on a rod 17 which loosely engages the plate 11 at its lower end. After an initial rapid movement, the piston 18 is slowed first by the oil trapped above it and then by a spring 22. The plate 11 is slowed by its tip 20 entering a narrow channel 25 to trap a quantity of oil which can only escape through a narrow vent 26. In a modification (Fig. 6, not shown) the plate 11 is stopped by spring urged resilient plates 31. Over the last part of the movement of the rod 17 a piston 16 thereon enters a channel 14 driving oil before it across the contacts to cool the arc. In the modification (Fig. 6, not shown) further blast action is brought about by gas evolving inserts 30 in the arc chamber 7. In a further modification (Fig. 12, not shown) pressure produced by the initial arc drives a differential piston 47 upwards compressing oil in a chamber 50 which thus moves downwards across the arc. In further modifications (Figs. 18-19, not shown) blast is produced by explosive capsules in the oil chamber. The tip 20 of plate 11 may be grooved to control the position of the arc (Fig. 8, not shown) and be provided with metallic or gas evolving inserts (Figs. 10, 9, not shown). Various forms of the arc chamber 7 are shown and described. In particular two parallel plates 11 may be provided moving in separate chambers (Fig. 11, not shown); magnetic blow-out coils (or permanent magnets) may be embedded in the chamber walls (Fig. 13, not shown); or the chamber 7 can be divided into several restricted chambers (Fig. 7, not shown). Contacts opened other than by the plate 11 may be employed and the use of main and auxiliary contacts is also suggested. The plate 11 can alternatively be moved by making piston 18 the movable core of an electromagnet. An overvoltage or lighting arrester may be connected in parallel with the breaker. A series isolator may be provided.