Rotary electric machinery

Abstract

A stator coil of a rotary electric machine includes a three-phase Y-form connection circuit including first windings Y1, Y2 and Y3, which are connected in Y-form, and a three-phase delta-form connection circuit including second windings .increment.x3, .increment.y3 and .increment.z3 which are connected in delta-form, wherein the second windings .increment.x3, .increment.y3 and .increment.z3 are sequentially inserted in slots of a stator core to have a phase difference of 120.degree. therebetween, and each of the first windings Y1, Y2 and Y3 is divided into two windings, and the divided first windings are separately inserted in the slots, in which the second windings .increment.x3, .increment.y3 and .increment.z3 have been inserted, so that the resultant composite voltage vector of each pair of the divided first windings is shifted by 30.degree. in phase from the voltage vector of one of the second windings .increment.x3, .increment.y3 and .increment.z3. By virtue of the foregoing structure of the rotary electric machinery, the number of slots decreases and an electromagnetic noise is reduced, since a magnetic force due to the air gap magnetomotive force distribution becomes substantially constant independently of a rotational position of a rotor.