GB364031A - Improvements in and relating to electric circuit breakers - Google Patents

Abstract

364,031. Oil-break switches. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Paul, W. E. ; 1048, Waverly Place, Schenectady, New York, U.S.A.) Sept. 26, 1930, No. 28918. Convention date, Sept. 26, 1929. [Class 38 (v).] In a liquid - break switch, the arc formed on breaking circuit is divided into series-connected sections and the pressure formed by one section is used to cause a blast of fluid across another section to rupture that other section.. A fixed contact 10 is located at the base of a metal oil pot 6 and is engaged in the closed position by a contact rod 2, which is arranged, in closing, to separate a pair of spring-pressed conducting members 17, 18, which are slidable in slots 16 in a partition 15. A further partition 22 receives the foot of an insulating surround 23 for the rod 2, and also supports a pair of cylinders 25, 26 containing pistons 27 and springs 28 therefor, the ends of the cylinders projecting down so as to open into the lower chamber under the partition 15. As the rod 2, in opening circuit, leaves the contact 10, an arc is drawn between the two and sets up an increase of pressure in the lower chamber, part of this increase being absorbed by the pistons 27. As the rod 2 moves through the members 17, 18 the arc is transferred to the latter, which now come together, and a further arc is set up between them and the rod 2. The pressure in the lower chamber, acting through an aperture 21 in the partition 15, directs a cooling stream of fluid across the arc in the upper chamber between the partitions 15, 22, the stream exhausting through an aperture 24 in the partition 22 into the main body of the housing 6. The pressure stored in the cylinders 25, 26 serves to prolong the stream after the effect of the initial arc has been spent, and the stream may be arranged to be confined within a narrow channel by restricting the size of the upper chamber. Two such rods 2 may be arranged in pots side-by-side and operated by a bridge carrying main air-break contacts, Fig. 1 (not shown). The rod may be arranged to move downwards instead of upwards, to break the circuit. Specification 193,136, [Class 38 (v), Electric switches &c.], is referred to.