Patent ID: 7183686

Claim:
A synchronous motor comprising: a stator including a stator iron core having two-pole windings wound therearound, the stator iron core having an inner cylindrical surface; a rotor including a rotor iron core rotatably accommodated facing the inner cylindrical surface of the stator iron core, the rotor including a plurality of conductor bars, positioned adjacent an outer periphery of the rotor iron core, and shortcircuit rings, positioned at axially opposite ends of the rotor iron core, the conductor bars and shortcircuit rings being molded together by aluminum die casting to form a starter cage conductor, the rotor having a plurality of magnet retaining holes defined therein on an inner side of the conductor bars; and permanent magnets embedded within the magnet retaining holes in the rotor and defining two magnetic poles of different polarities; wherein the shortcircuit rings have an inner diameter positioned outwardly from associated magnet retaining holes, an inner diameter of the shortcircuit rings at a location adjacent one end of the magnetic poles being larger than an inner diameter at a location adjacent an intermediate point of the magnetic poles; and wherein the stator iron core comprises a stator laminate of electromagnetic steel plates and the rotor iron core comprises a rotor laminate of electromagnetic steel plates, a thickness of the stator laminate and a thickness of the rotor laminate being substantially the same.