GB181530A - Improvements in high resistance conductors, for electrical machinery - Google Patents

Abstract

181,530. British Thomson - Houston Co., Ltd., and Taylor, H. W. April 4, 1921. Coils and conductors; alternating-current induction machines.-In windings for dynamoelectric machines, such as induction motors, having two or more composite conductors per slot with intervening magnetizable material to give an equivalent resistance which increases with the frequency, as described in Specification 180,765, the composite conductors are made up with two or more sections, the outer sections having higher resistance than the inner sections. As shown in Fig. 1 conductors A and B are composed of three sections a, b, c and d, e, f respectively and the central sections band e have a larger cross-section than the others. As the induced eddv currents are limited to the outer members, a high equivalent resistance increase is obtained with increasing frequencies. The sections may all form closed coils and may be insulated from each other throughout their length or, as shown at A, Fig. 2, they may be joined together at both ends of the core, such triple conductors forming the upper bars in the slots while double conductors B form the bottom bars. The conductors mav also be used in squirrel-cage rotors.