Revolving magnetic field type motor

摘要

A revolving magnetic field type motor has a rotor and a stator. The rotor has a plurality of permanent magnets. The permanent magnets defines a plurality of rotor magnetic poles. The number of the rotor magnetic poles is "P". The rotor has a plurality of blocks aligned in the rotor's axial direction. The number of the blocks is "m". Each block has a set of the rotor permanent magnets. One set of the permanent magnets is offset relative to an adjacent set of the permanent magnets by a predetermined offset angle in the rotor's rotational direction. The stator has a plurality of coils, the coils defining a plurality of stator magnetic poles around the axis of the stator, the number of the stator magnetic poles being "T". The predetermined offset angle is selected from within a range from about zero degrees/((m-1)xn) to about 22.5 degrees/((m-1)xn). The number of the rotor magnetic poles "P" is 8n (n is an integer equal to or greater than one). The number of the stator magnetic poles "T" is 9n (n is an integer equal to or greater than one). This motor reliably decreases cogging torque.