GB689045A - Improvements in polyphase heteropolar inductor alternators - Google Patents

Abstract

689,045. Inductor alternators. BRITISH THOMSON-HOUSTON CO., Ltd., and RABY, K. F. Feb. 23, 1951 [March 15, 1950], No. 6508/50. Class 35. An n-phase heteropolar inductor generator (n>2) has each exciting pole with n teeth bounded by the exciting winding and each tooth is embraced by a winding belonging to one of the n phases which is connected in series-aiding with a corresponding winding embracing a tooth spaced from the first tooth an odd multiple of # radians and located under an exciting pole of opposite polarity, the windings on adjacent poles being arranged in a different phase sequence. Fig. 2 shows a three-phase alternator in which each pole of stator S has three teeth, e.g. F, G, H bounded by an exciting winding E1 in large slots. In the pole under consideration, the teeth F, G, H are respectively embraced by the phase windings A, C, B and in the next pole the corresponding phase windings B1, Al, C1 embrace teeth F1, G1, H1. The pole pitch of the stator teeth is an odd multiple of # to enable the phase windings to be connected in series-aiding so as to have output E.M.F. without even harmonics. The polo pitch of the rotor teeth TR is 2#. The phase windings under one pole are connected in seriesaiding to the corresponding phase windings under the next pole and so on for the rest of the windings under the other poles. Fig. 3 shows the A.C. windings A, C, B and B1, A1, C1, &c. arranged to avoid their location in slots occupied by the exciting windings and, in consequence, under each exciting pole there are teeth embraced by a whole winding of one phase, and teeth embraced by two half-windings of the other two phases, the other half-windings of these phases embracing teeth under the other poles. In Fig. 4, the n-teeth under a pole are longer and are sub-divided into smaller unwound teeth so as to generate higher frequency current. Specification 622,190 is referred to.