Difference between Synchronous Motor and Asynchronous Motor

Synchronous motor means that the rotor speed of the motor is equal to the electromagnetic speed of the magnetic field generated by the stator winding, so it is called a synchronous motor.

Asynchronous motor means that the rotor speed is not equal to the electromagnetic speed of the magnetic field generated by the stator winding, so it is called an asynchronous motor.

From the concept, it can be seen that the speed of the synchronous motor is constant, and the motor speed is equivalent to the electromagnetic speed generated by the stator winding, which does not change with the load; while the actual speed of the asynchronous motor is lower than the synchronous (asynchronous), and the speed is close to the synchronous with the rated load. , decreases as the load increases.

Why is there such a difference between an asynchronous motor and a synchronous motor? The most fundamental reason is actually whether the stator of the motor has problems such as weak excitation, non-excitation and asynchronous, because only relative motion can be used to cut the magnetic field line (or the magnetic flux change). The electromagnetic induction force (that is, the ampere force) is generated, and the rotating magnetic field and the rotor have a relative rotation speed, that is, the rotation speed is generated. With the addition of excitation, the stator can be regarded as a magnet with a fixed NS pole, which generates a magnetic field in a fixed direction and rotates synchronously with the rotating magnetic field, so it is called a synchronous motor. (attraction of magnets).

Most asynchronous motors are only used as electric motors, while synchronous motors are used to generate electricity. In addition, due to the advantages of simple structure, convenient manufacture, low price and convenient operation, asynchronous motors are also widely used in practical applications. For example, the most widely used Y series three-phase asynchronous motors in production are ordinary asynchronous motors. Representative of the motor.