Improvements in and relating to electric transformers and like apparatus

摘要

171,251. British Thomson - Houston Co., Ltd., (General Electric Co.). Sept. 15, 1920. Transformers.-In an air-core reactance or transformer 10 enclosed. in a metal casing 12 containing a cooling and insulating medium such as oil, a magnetic shield, adapted to be traversed by shortcircuited currents, is placed about the internal wall of the casing in order to confine the stray flux emanating from the windings. The shield may comprise a sheet of copper 15, Fig. 1, lining the inside of the casing, or it may be composed of a number of separate rings or strips of copper. In the arrangement shown in Fig. 6, in which an auxiliary cooling medium in the form of water or other liquid circulating through coils 50 is employed, the coils 50 serve as the magnetic shield, the top and bottom convolutions being connected by a short-circuiting member 53. Separate shields are employed around each of the coils of polyphase apparatus.