GB217290A - Improvements relating to electrical switch gear - Google Patents

Abstract

217,290. Christianson, T. C., and Metropolitan-Vickers Electrical Co., Ltd. March 8, 1923. Oil switches; switchboards. - In ironclad switchgear the connections between the oil switch contacts and the feeders, bus-bars &c. are in the form of removable plugs which are inserted individually through openings in the armouring to engage corresponding socket members. As applied to a three-phase truck type switch gear unit Fig. 1, the stationary member comprises three chambers 12, 13, 14, the lower of which serves as an entry for the feeder 26 and the other two as housings for alternative sets of bus-bars 24, 25. The cores of the cable 26 are connected to socket contacts 17 held in insulating tubes 11, each bus-bar being joined to a socket 15, 16 within tubes 9, 10 in the corresponding chamber. The movable truckmember carries an oil switch 1 with hood 2 through which pass corresponding insulating tubes 6, 7, 8. Within these tubes are annular contacts 34, 35 in connection with the oil switch contacts 27, 28 respectively. Removable plugs 29 are adapted to be inserted in the openings in the hood 2 to bridge socket contacts therein and so permit the feeder 26 to be connected by the switch 1 to one or other of the sets of bus-bars 24, 25. To prevent both sets of bus-bars being alive simultaneously hinged flaps 35 are provided to cover one or other sets of socket holes. Each plug has an insulating handle 30 enabling it to be withdrawn without first removing the truck. To prevent withdrawal of the plugs while the switch 1 is closed a plate 32 is held against them by a projection 33 on the switch operating shaft 34. The plug members may be modified to earth parts of the gear or to lead current from the bus-bars &c. to testing instruments. Where it is desired to break contact between the plug and socket members under an <*> insulating liquid, their axes may be suitably inclined so that the sockets form oil receptacles. It it is desired to change the bus-bars connection without interrupting the supply, the interlock between the plugs and switch is omitted, and a switch for temporarily interconnecting the two sets of bus-bars is provided.