GB769406A - Improvements in metal-clad electric switchgear - Google Patents

Abstract

769,406. Switchgear structures. BRITISH THOMSON-HOUSTON CO., Ltd. March 2, 1955 [March 4, 1954], No. 6380/54. Class 38(5) In metal-clad switchgear of the withdrawable type, contacts are provided on the fixed part of the gear which are spaced apart by a distance equal to that between the circuit-breaker terminals 18 and which are connected respectively to a bus-bar, to earth and to a circuit which is, in a predetermined position of the circuit-breaker, controlled by the circuit-breaker, a separate potential transformer terminal being provided in electrical connection with, but remotely situated from, the circuit contact, the arrangement being such that by a process of withdrawal, transverse movement, and entering, the circuit-breaker 15 can be caused to control the earthing of the bus-bar or of the circuit without the removal of any other component from its normal operative position. The fixed position of the gear may comprise duplicate bus-bars 2 3 having contacts 10, 11 arranged each side of circuit contact 9. Earthing contacts 12, 13 are arranged adjacent contacts 10, 11 respectively, and a further contact 14 is provided which is connected to circuit conductor 6 between a cable entry box 4 and current transformers 8. A voltage transformer 19 is connected to conductor 6 via a terminal 20 engaging fixed contact 21. By lowering the circuit-breaker on its truck 16, moving the carriage 17 on which it is mounted and raising the circuitbreaker, terminals 18 may be caused to engage any two adjacent fixed terminals 9 to 14. Specification 686,684 is referred to.