Synchronous motor

A synchronous motor driven by a two-phase alternating current composed of a first-phase alternating current and a second-phase alternating current which have a phase difference with respect to each other, the synchronous motor comprising:

• a rotor that includes a plurality of magnetic poles arranged at equal intervals in a circumferential direction;
• and
• a stator that includes an annular yoke and N teeth arranged at intervals on the yoke in the circumferential direction, N being an integer of four or greater, wherein
• the stator is configured such that the N teeth (i) include sets of n teeth, n teeth in each set being disposed at a same position in terms of electrical angle, and (ii) are grouped into first groups of k teeth, k teeth in each first group being aligned in the circumferential direction, each first group being rotationally symmetric about an axis of the yoke, n and k each being an integer of two or greater, and N=k·n,
• one of the k teeth in each first group is a reference tooth, and at least another one of the k teeth in the first group is a displaced tooth which is displaced from a position corresponding to an integral multiple of the phase difference with respect to the reference tooth in electrical angle,
• only either one of first-type coils or one of second-type coils is wound on the reference tooth by concentrated winding, the first-type coils being supplied with the first-phase alternating current, and the second-type coils being supplied with the second-phase alternating current,
• both one of the first-type coils and one of the second-type coils are each wound on the displaced tooth by concentrated winding,
• first-type coils wound on the teeth in each first group are connected in series, and
• second-type coils wound on k teeth, aligned in the circumferential direction, in each of second groups are connected in series, the second groups being either same or different with respect to the first groups.