1. The electromagnetic torque of the synchronous motor is the interaction between the rotating magnetic field of the stator generated by the power supply voltage and the main magnetic field of the rotor;

2. The angle of intersection of the rotating magnetic field of the stator and the magnetic pole axis of the main magnetic field of the rotor is called a power angle;

3. When the power angle is zero, the electromagnetic torque is zero. The larger the power angle is, the larger the torque is. The larger the stator current is, the more the elongation of the rope is, the larger the pulling force is when you pull the car.

4. Of course, when the power angle is close to 90 degrees, the torque is the largest and the current is the largest;

5. When the power angle is greater than 90 degrees, the torque starts to decrease and enters the unstable running area. At this time, it will lose the step quickly, which is equivalent to pulling the rope when the pulling rope is broken!

6. The physical quantities related to the size of the power angle are:

1) electromagnetic torque;

2) stator current;

3) output power (related to the speed);

7. When the power angle increases from zero to 90 degrees, the current, torque, and power are monotonically increasing functions. Simply put, the current, torque, and power increase as the power angle increases.

8. As long as the magnitude of the synchronous motor current is detected, the magnitude of the power angle and the magnitude of the torque are known!

9. For example, if you detect that the current of the synchronous motor is the rated current, then it is needless to say that the power angle is the rated power angle, and the torque is the rated torque!

10. For synchronous motor, the frequency conversion start starts from zero HZ, and the current increases from zero. When the current increases to the rated current, the power angle is the rated power angle, and the torque is the rated torque. At this time, the power is the smallest. When the speed increases to the rated speed, the power reaches the rated power!

11. As long as the control current is the rated current, the power angle is the rated power angle, and the torque is the rated torque!

12, in the case of a certain current, you can also increase the voltage, enhance the magnetic field, increase the torque, this is the second way of torque control!