GB385316A - Improvements in electric circuit interrupters with contacts immersed in oil or otherinsulating liquid - Google Patents

Abstract

385,316. High-tension switches. PEARCE, H., Green Mount, Barrington Road, Altrincham, Cheshire, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. April 20, 1931, No. 11675. [Class 38 (v).] Oil switches of the type having a bridging contact 12 carrying spring contacts co-operating with fixed contacts 6, 7 to give two breaks per phase are provided with a fixed insulating chamber or cellular structure which constitutes the equivalent of two explosion pots one for each phase with a passage between them and a vent at one side so that the pressure produced at one break may serve to quench the arc 'at the other. In the arrangement shown in Fig. 1, the structure consists of two U-shaped insulating or insulated plates 2, 3 fitting into one another, closed at their outer ends by wood blocks 4, 5 and supported from the fixed contacts 6, 7 so as to constitute a chamber 1 in which the fixed contacts are located. The plate 3 has orifices for the passage of the movable contacts, that for the contact 8 being larger than the other. These orifices communicate with the outer oil in the tank through the chamber 1 and the opening between the plates at the right-hand side. The left-hand contact is arranged to break circuit first ; it develops an oil pressure which quenches the second arc. In a modified construction, Fig. 2, a series of spaced insulating plates 2, 3, 22, 23 with orifices for the movable contacts are used. The spaces between these plates constitute deionizing chambers which are closed at the sides and alternate chambers closed at opposite ends.