Abstract: A three-phase permanent magnet-type synchronous motor configured to significantly reduce cogging torque. The motor includes a rotator and stator each having either permanents magnets or teeth. The number of magnetic poles of the rotator or stator is P and a number of slots of the stator or rotator is N, and a fraction of 2N/3P has a value greater than zero and less than one. The tooth width of the teeth of the stator or rotator in a circumferential direction is ½ of the slot pitch of the stator or rotator.

Abstract: A cogging torque can be significantly reduced in a three-phase permanent magnet-type synchronous motor. In a three-phase permanent magnet-type synchronous motor where a fraction of 2N/3P is not an integer assuming the number of magnetic poles of a rotator is P and the number of slots of a stator is N, the stator includes a tooth facing a surface of a magnetic pole of the rotator via a void and a tooth width of the tooth in the circumferential direction is approximately ½ of a slot pitch of the stator. In a three-phase permanent magnet-type synchronous motor of an outer rotor type, the tooth of the stator has a radial cross section with an approximately uniform shape from a tooth tip portion to a tooth root portion or a radial cross section with a larger tooth root portion than a tooth tip portion to allow mounting a winding unit from the tooth tip portion. The winding unit is preliminarily wound by a coil.