Patent GB-341188-A (GB)
Title: Improvements in or relating to electrical switchgear
IPC: H02B11/18
Filed: 1929-11-15
Abstract: 341,188. Switchgear structures. DAVIES, D. R., 14, Ruabon Road, Didsbury, near Manchester, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Bush House, Aldwych, London. Nov. 15, 1929, No. 34952. [Class 38 (v).] Structures of the type in which isolation is effected by bodily raising or lowering the breaker, have the latter slidably mounted on guides which engage directly with the breaker structure and serve the dual purpose of guiding the vertical movement of the breaker between the isolated and service positions and of securing the breaker in either of these positions, by means of one or more locking abutments associated with the guide members. In the simple form shown in Fig. 1 a circuit-breaker 1 is provided with isolating contacts 6, 7 by which it is adapted to connect the bus-bars 3 with a feeder 2 when lifted, as by an overhead crane, into its raised position. The breaker 1 is guided in this vertical movement by posts 11, preferably four in number, the posts being of square or other non-circular section, or of cylindrical section and providedwith keys or feathers. The head 13 of the breaker is provided with correspondingly shaped apertures 12 or collars to receive the posts 11, the latter having ends of circular section. By means of a hand-wheel 23 and gearing, the posts may be simultaneously rotated through a small angle to bring them into and out of register with the openings 12, whereby the breaker can be supported in service or isolated position or unlocked to allow connection and disconnection. Detachable collars 24 allow suspension of the head 13 when the tank 25 is to be removed. In switchgear for extra high voltage, Fig. 2, a breaker 1 is shown on the left in isolated, raised position and another breaker on the right in service position, lifting being effected by a crane 28, and hooks 30 engaging eyes 31 in the head 13. Closing gear and trip mechanisms are located in a casing 32 and the closing coil in a casing 33. Guide-pillars 11 are mounted in bearings 34, 35, the latter being carried on a casing 36 on the fixed part 37 which carries in oil-filled casings 8, 9 the contacts co-operating with contacts in oil-filled casings 37, 38 in the movable part of the gear. The posts 11 are rotated by a hand-lever 44 through a lever 42 and links 39, one of which operates a switch 45 controlling the energizing of the closing coil to prevent the breaker from being closed unless it is locked in service position. The closing mechanism in the casing 32 operates through a lever 47 and link 48 a switch 46 for operating an indicator, the lever and link serving also to operate a sliding bolt 55 to prevent the posts 11 from being rotated to unlocked position unless the breaker is open. The head 53 of a bolt 51 is actuated by a cam 52 from the lever 44 to prevent insertion of the hook 30 in the eye 31 while the posts 11 are in the locked position. The lever 44 cannot, further, be moved to the locked position until the hook is removed from the eye. Plugs and sockets in casings 49, 50 may be provided for auxiliary connections between the fixed and moving parts of the structure.