| 摘要 |
PROBLEM TO BE SOLVED: To reduce cogging torque of an AC motor having such structure as two polar-anisotropic magnets are stacked in an axial direction. SOLUTION: The AC motor comprises a ring magnet 3 of a field magnet on a rotor side and an armature on a stator side. Related to the ring magnet 3, two ring polar-anisotropic magnets 3a and 3b are so engaged and fitted as to be stacked in axial direction shifted in circumferential direction by a prescribed angle, on the outer peripheral surface of a rotor body 2. The prescribed angle is acquired by dividing 360°in circumferential direction, with a least common multiple of the number of magnetic poles and the number of slots, which is multiplied with the logarithm of magnetic pole and then divided by 2 for the center of magnetic poles of the two poler-anisotropic magnets 3a and 3b. COPYRIGHT: (C)2004,JPO
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