Fundamental Examination of Hybrid Type Double Three-phase Stepping Motor

In improving the resolution of hybrid type stepping motor, there are a method of increasing the number of rotor teeth and a method of increasing the number of phases. The method of increasing the number of rotor teeth comes for the limit to exist from respect of the machining and the increase in the number of rotor teeth causes the deterioration of high-speed characteristics. On he other hand, the method of increasing the number of phases brings the cost amount from becoming of the drive circuit the complexity.

In this paper, aiming at improvement of resolution of HB Type stepping motor, double 3-phase stepping motor are examined which has 2 sets of 3-phase stator windings. It has the half step angle as 3-phase stepping motor with the same number of rotor teeth. It is shown that double 3-phase motor has 2 types of construction which are different in magnetic path (multi-phase magnetic path type and uni-phase magnetic path type). In each type, how to choose the number of rotor teeth and stator magnetic pole intervals to compose double 3-phase stepping motor are examined, and the motor characteristics are compared multi-phase magnetic path type with uni-phase magnetic path type.