According to statistics, the classification of AC motors can be in the following two ways:
By function
AC motors are usually divided into several categories according to their functions: alternator, AC motor and synchronous camera. Due to the reversibility of the working state of the motor, the same motor can be used as both a generator and a motor.
It is not very accurate to divide the motor into a generator and a motor, but some motors mainly operate as generators, and some motors mainly operate as motors.
By variety
AC motors are divided into synchronous motors and asynchronous motors by type. The speed ns of the synchronous motor rotor is the same as the speed of the rotating magnetic field, which is called the synchronous speed. There is a strict relationship between ns and the frequency of the connected alternating current (f) and the number of pole pairs of the motor (P).
ns = 60f / P
In China, the power frequency is 50 Hz, so the synchronous speed of one pair of pole motors in a three-phase AC motor is 3000 rpm, the synchronous speed of two pairs of pole motors in a three-phase AC motor is 1500 rpm, and so on. The speed of the rotor of an asynchronous motor is always lower or higher than the speed of its rotating magnetic field, hence the name asynchronous. The difference between the rotor speed of the asynchronous motor and the rotating magnetic field speed (called slip) is usually within 10%.
