GB377707A - Improvements in and relating to electric circuit breakers - Google Patents

Abstract

377,707. Oil switches. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Turnpenny, W. H. ; 12-c, Wilkins Avenue, Albany, and Skeats, W. F. ; 211, 2nd Street, Scotia, both in New York, U.S.A.) April 23, 1931, No. 12121. Convention date, April 23, 1930. [Class 38 (v).] Two breaks between two pairs of abutting contacts in series are produced within the oil-filled explosion pots (one only of which is shown) of a switch. As the bridging contact member 7 with the tubular contact 6 is moved downwards, the floating intermediate contact 5 follows it under the action of the spring 24 and the spring-mounted main contact 4 also follows under the actions of its spring 10. After a small combined movement, the contact 4 is held up by a conducting inner portion 8 of the container. An arc is then drawn between the abutting contacts 4, 5 and when, soon afterwards, the intermediate contact 5 (which carries a spider 22 against which the spring 24 bears) is held up in turn by a cupped insulating disc 1, the tubular contact 6 is withdrawn from abutting engagement with the flat face 26 of the intermediate contacts. The pressure produced at the first arc now forces oil radially across the second, down the tubular contact 6 and out through passages 28 or through the open end of the contact into the main body of the oil. When very heavy currents are interrupted, the oil pressure developed may cause the contact 4 to " pop-back " notwithstanding the provision of pressure equalizing passages 8a. In this event the arc moves over to the flared lower sides of the portion 8. An orifice 12a prevents air locks so that the explosion chamber can fill up again with oil. An insulating liner 13 shields the explosion chamber from flash-over. Specifications 13852/02, [Class 38, Electricity, Regulating &c.], and 193,136, [Class 38 (v), Electric switches &c.], are referred to.