GB548394A - Improvements in electric transformers - Google Patents

Abstract

548,394. Transformers. BRITISH THOMSONHOUSTON CO., Ltd. May 21, 1941, No. 6504. Convention date, May 24, 1940. [Class 38 (ii)] A current transformer comprises a pair of cascadeconnected units each comprising a ring core 19, 48 surrounded by primary and secondary windings which are separated by solid porous insulation such as crepe paper 20, 44 surrounded by an impervious covering 27, 42 the two coverings being extended about the interconnecting leads 23, 39 for the two units and being interconnected in a fluid-tight manner, a valve 33 being provided to permit fluid to pass between the units when assembled and to seal off the upper unit when it is removed from the lower unit. The transformer units are generally similar as regards the insulation arrangement to those described in Specifications 537,206 and 539,730, the space within the impervious covering being filled with a gaseous or liquid dielectric such as dichlordifluormethane or oil, leakage being prevented during assembly by closure of the valve 33. When the two units are assembled, electrical connections are made by engagement of pins 40 with sockets 41, and the valve 33 is opened by engagement of stem 34, Fig. 3 with bar 38. Casings 10, 11 surrounding the transformer units are interconnected by a hollow cylindrical insulator 12 and the space so formed is filled with an insulating fluid. Where this fluid is different from that used within the impervious covering, a small conservator tank is provided in the space between the covering and the outer casing, the tank being in communication with the space within the covering.