If you buy ac synchronous motor, you need to know how to start the synchronous motor
The starting synchronous motor can produce the average torque only at the synchronous speed. If the stator is connected to the grid immediately at startup and the rotor is subjected to DC excitation, the stator rotating magnetic field immediately rotates at a synchronous speed, and the rotor magnetic field is temporarily stationary due to the inertia of the rotor. At this time, the electromagnetic torque generated will change the positive and negative intersections and its average value is zero, so the motor can not start on its own. To start a synchronous motor, you must use other methods. There are two main methods.
