GB1484193A - Electric induction machine winding - Google Patents

Abstract

1484193 Winding layouts in dynamo-electric machines AGENCE NATIONALE DE VALORISATION DE LA RECHERCHE 12 Aug 1974 [17 Aug 1973] 35518/74 Heading H2A In a pole changing polyphase induction machine winding, the winding coils are divided into a plurality of consecutive sets, the coils of one set remain connected to their respective phases when switching from one pole member to another, whereas the coils in each of the other sets are phase shifted by respective predetermined amounts, though some of the coils may be omitted in order to give a balanced winding for the second pole member. In general, if the coils are divided into m consecutive sets of successive coils, then the coils of the rth set, where r = 0, 1, 2 ... (m-1), are phase shifted by +2#r/m if the second pole member is 2 lower than the first and by - 2#r/m if the second pole member is 2 higher than the first. Thus in a 6/4 pole winding where the coils are divided into 3 sets (m = 3), the coils of one set (which is chosen to be centred on a pole of the four pole winding configuration) remain unaltered in phase when switching over from 4 poles to 6 poles, whereas the coils in the next set are respectively phase shifted by 2#/3 and the coils of the last set are shifted by 4#/3. Where the difference between the two pole members exceeds 2, say q.2, then the coils are first divided into q successive groups round the machine periphery and the division into m sets (with the consequent phase shifting of coils) is then performed within each group. The coils may be connected in a triple parallel star arrangement, Fig. 13 (not shown), the ends of the star arms being supplied for one pole member and the neutral points for the other. Coils omitted to ensure a balanced winding may form a fourth star (Fig. 15) or a delta (Fig. 16) in parallel with the three stars. They may alternatively be connected between the terminals and the ends of the star arms and/or the neutral points.