In the motor test or initial design stage, the rotation direction of the motor needs to be considered, and how to design the three phases of the winding is related to the rotation direction of the motor.

If you talk about the rotation direction of the motor, many people will think it is very simple, and the rotation direction of the distributed coil motor or the motor with the concentrated coil q=0.5 is well determined. The following describes the determination of the rotation direction of a 6-pole 9-slot motor with q=0.5, and the method of determining the rotation direction of a 10-pole 9-slot motor with q=3/10.

For a 6-pole 9-slot motor, the electrical angle of the slot is 3*360/9=120 degrees, so adjacent slots are adjacent phases. For the 1, 2, and 3 teeth in the figure, the lead wires are respectively led out, which is finally defined as the ABC phase. Above we have calculated that the electrical angle between 1, 2-2, 3-3, 1 is 120 degrees, but we don’t know whether it is a lead or a lag relationship.

If the motor rotates clockwise, you can observe the peak of the back EMF, the 1st tooth peaks first, then the 2nd tooth, then the 3rd tooth. Then we can connect 1A 2B 3C, so that the wiring motor rotates clockwise. The idea of ​​this method is that the phase relationship of the back EMF of the motor corresponds to the power supply that energizes the phase winding.

If the motor is spinning counterclockwise, tooth 3 peaks first, then tooth 2, then tooth 1. So the wiring can be 3A 2B 1C, so that the wiring motor rotates counterclockwise.

In fact, the rotation direction of the motor is determined by the phase sequence. The phase sequence is the sequence of phases and phases, not a fixed position, so it corresponds to the phase sequence of 123 teeth: the wiring method of ABC, CAB, and BCA. In the above example, the rotation of the motor The directions are all clockwise. Corresponding to 123 teeth: CBA, ACB, BAC wiring mode The motor rotates counterclockwise.

This motor has 20 poles and 18 slots, and the unit motor corresponds to 10 poles and 9 slots. The slot electrical angle is 360/18*10=200°. According to the winding arrangement, the 1-2-3 windings differ by 3 slots, corresponding to a difference of 600° electrical angle. The 600° electrical angle is the same as the 240° electrical angle, so the motor 1-2-3 The included angle between the windings is 240°. Mechanically or physically (or in the above picture) the order of 1-2-3 is clockwise, but in electrical angle 1-2-3 is arranged counterclockwise as shown below, because the electrical angle difference is 240 °.

1. According to the physical position of the coils (clockwise or counterclockwise), draw the electrical relationship of the three-phase windings in combination with the phase difference electrical angle, analyze the rotation direction of the magnetomotive force of the windings, and then obtain the rotation direction of the motor.

2. In fact, there are two situations in which the electrical angle difference of the motor is 120° and the difference is 240°. If the difference is 120°, the rotation direction is the same as the 123 space arrangement direction; if the difference is 240°, the rotation direction is opposite to the 123 winding space arrangement direction.