Patent ID: 7425786

Claim:
A permanent magnet type rotating electrical machine comprising: a stator; and a rotor disposed opposite to said stator with a gap left therebetween; wherein, said stator comprises a stator core and stator windings wound over said stator core; said stator core comprises an annular yoke core and a plurality of teeth cores radially projecting from said yoke core; said rotor comprises a rotor core and a plurality of permanent magnets embedded in said rotor core; a pair of nonmagnetic portions are formed in said rotor core at circumferential opposite ends of said permanent magnet for each magnetic pole; a pair of magnetic path portions are formed by said pair of nonmagnetic portions in areas of said rotor core which are positioned on one side of said pair of nonmagnetic portions closer to said stator; and assuming that a circumferential pitch of said teeth cores with respect to an axis of said rotor is τs (degree) and an opening angle contained by a circumferential width between radial width minimum points of said pair of magnetic path portions with respect to the axis of said rotor is θ (degree), the following formula is met θ≈(n+Y)×τs(n: integer larger than 0) where Y=0.5 when said stator windings are wound in a distributed winding way, and Y=0.9-1.2 when said stator windings are wound in a concentrated winding way.