GB327683A - Improvements relating to electric switchgear - Google Patents

Abstract

327,683. British Thomson-Houston Co., Ltd., Wellings, J. G., and Adams, W. S. Jan. 3, 1929. Transformers. - In order to isolate the potential transformers of metal-clad hightension switchgear, they are connected with the live conductors 5 by means of a connection secured to the cover 14 by means of an insulating link 13 and removable with the cover. In this removal, the fuse link 7 (which, as usual, forms part of the connection to the live conductor) is connected to earth by engaging with spring contacts 10 mounted in the sides of the orifice in the earthed casing through which the connection is withdrawn. In the fully withdrawn position, a contact-member 12, detachably secured to the fuse by the bolt 23 and carrying at its other end a contact 24, normally abutting against a fixed terminal contact 4 in the end of a hollow bushing 2, is brought into engagement with clip contacts 6 mounted at the upper end of the housing. This provides a circuit from the transformer primary (connected to terminal 9 of the housing) through the current-limiting resistance 8 which is wound round the housing and may serve as a screen for preventing corona discharge as described in Specification 300,234, thence by a lead connection to the contacts 6, contacts 12 and to the fuse which connects with earth through the contacts 10. Contacts 25, 26 may be provided on the cover and tank so that, when the cover is removed, the secondary circuit of the transformer is disconnected.