GB458431A - Improvements in metal-clad electric switchgear - Google Patents

Abstract

458,431. Switchgear structures. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, GIMSON, C. F., 41, Princes Avenue, Gunnersbury Park, and REGIS, E. D., 43, Tanfield Avenue, Cricklewood, all in London. June 20, 1935, No. 17740. [Class 38 (v)] A single-phase metal-clad switching unit comprises a single-break explosion pot circuitbreaker with horizontal contact separation mounted above a chamber or chambers containing fixed contact structures associated respectively with the bus-bar and the circuit to be connected thereto through the breaker, and vertically-movable isolating members for effecting the connection between the contacts of the breaker and the contact structures aforesaid. The explosion pot 2 is mounted on a bushing insulator 3 supported with liquidtight joints by the chamber 1 containing the operating mechanism 26 of the co-operating movable contact 14. The insulator 3 is kept filled with oil from chamber 1 and contains a fixed isolating plunger contact 5 co-operating with a vertically-sliding rod 6 which is in engagement with a garter contact 4. A similar insulator 12 supporting the garter contact 13, in which the contact 14 slides, contains a plunger contact 20, an isolating rod 19, and a garter contact 18. The insulators 3, 12 are surrounded by current transformers 24 and terminate in their respective chambers 8, 15 connected to the chambers 11, 17 of a cable 10 and bus-bar 16. For polyphase gear, the chamber 15 may have three openings, provided with cover plates, at different angles for connection to a plurality of chambers 17. The upper ends of 6, 19 are threaded to engage nuts 23 on insulators 21 secured to earthed rods 22, so that by rotating a handle 23a the rods can be earthed at 22 and the breaker itself inspected. Alternatively, rods 6, 19 may terminate in the insulators 21 which may slide on rods 22 secured to the chamber. Polyphase gear may comprise a number of separate singlephase units, or a number of single-phase elements embodied in a common outer casing.