Three-phase stepper motor structural characteristics and technical parameters

It is assumed that the rotors are all PM type or HB type, and two-phase, three-phase, and five-phase rotors are respectively equipped according to the stator. The stator adopts a structure with the smallest number of main poles that does not produce unbalanced electromagnetic force, that is, four main poles and three main poles for two phases. When the phase has three main poles and the fifth phase has five main poles, unbalanced electromagnetic force will be generated in the structure. The above structure should not be used except for special purposes.

Stepper motor phase number and drive circuit

On the other hand, for the stepper motor drive circuit used for bipolar coils, since the windings adopt Y or Δ connection, the number of power tubes is 8 for two phases, 10 for five phases, and three for three phases. According to legal regulations, only 6 power tubes are enough to drive three outlet ports. Therefore, considering the integration of the motor and driver, the three-phase stepper motor has a simple structure and the lowest manufacturing cost.

Judging from the odd and even numbers of the stator phases, the number of switching power tubes in the drive circuit under odd numbers is less than that under even numbers. For example, a three-phase stepper motor has fewer drive power tubes than a two-phase stepper motor. Compared with two-phase stepper motors, three-phase stepper motors have the advantages of 1.5 times higher resolution and lower vibration when the number of rotor teeth is the same.

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