It is made easy for a stator winding to be wound around a stator core and degradation in efficiency is prevented as much as possible. A stator (6) includes a plurality of phases, i.e., of circumferentially divided stator magnetic poles (6a, 6b, 6c). The stator magnetic poles (6a, 6b, 6c) are each composed of an arcuate stator core (13) having a plurality of axially extending claw poles (16b) and a circumferentially elliptically wound stator winding (14). The stator magnetic poles (6a, 6b, 6c) are magnetically divided; therefore, magnetic flux leakage is reduced to improve efficiency. Air flowing between the stator magnetic poles (6a, 6b, 6c) can improve a cooling effect.