This paper analyzed the characteristics of the claw pole PM step motor by using 3D FEM. As the magnetization occurs along the z-axis of the motor, it is necessary to apply 3D FEM for analysis of the claw pole PM step motor. Since a phase difference of a detent torque is 180 degree, a small detent torque is produced because of cancelling each other when the center of a permanent magnet is identical with the middle of a pole in an ideal case. In some manufacturing procedures, however, construction errors, which are a discrepancy between one and the other phase section, are probably occurred so that the detent torque increases. Also, it is confirmed that proportions of the detent torque considerably arise according to the error. The analysis was carried out including the range to be from 0 to 3 degree.
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