Coils in respective poles are all wound in the same shape. The coils are wound such that one of the winding ends in a predetermined layers, for a single turn, is passes to an adjacent layer, or single turns at the winding ends in a predetermined layer are wound to different adjacent positions, whereby the cross-sectional shape of the coils is unsymmetrical. The coils are wound such that part of each coil crosses or contacts an intermediate line bisecting the angle formed between the axes of the coils.