GB301101A - Improvements in or relating to electrical switchgear of the metal clad type - Google Patents

Abstract

301,101. Davies, D. R., and Metropolitan-Vickers Electrical Co., Ltd. July 25, 1927. Transformers. - In metal - clad switchgear arrangements in which the casing of an oil break switch, such as an isolating or selector switch contains auxiliary apparatus such as a potential transformer, devices for use with such apparatus as a fuse and limiting resistance, are arranged to be disconnected and withdrawn through an opening in the switchgear casing whereby they may be safely handled without putting the switchgear out of service. As shown in Fig. 2 in which a potential transformer 2 is mounted within an oil-filled casing 1 containing an isolating or selector switch the fuse 23 and limiting resistance 24 are mounted on a movable carrier 19 bearing contacts 29 engaging fixed contacts 28. When it is desired to inspect or renew the fuse or resistance the carrier 19 is raised to the dotted position by screw and nut gear 13 operated through bevel gearing 21. The lid 11 of a hood 10 on being opened, enables any replacements to be effected. During the raising of the carrier its contacts are disengaged from the cooperating fixed contacts so isolating the auxiliary devices 23, 24. Arrangements for earthing the carrier in its position may also be provided. If it is desired to test the cable the carrier 19 may be removed from its holder and replaced by a bracket 41 (Fig. 3) carrying an insulated rod 43 terminating at its lower end in a spring contact 44 for engagement with the fixed contact 28 passing to the cable. Thus connection of the cable to external devices may easilv be effected. A second bracket 45 acts as a stop to indicate the correct position of the conductor 43 when lowered into contacting position. Specification 196,369 is referred to.