Classify motors by speed

Classification of speed characteristics of electric motors

(1) A constant speed electric motor. Speed and load are not classified (e.g. synchronous motor).

(2) An electric motor with almost constant speed (parallel excitation characteristics). The rotational speed only varies slightly with the load (for example, synchronous motors and asynchronous motors).

(3) An electric motor with appropriate speed variation (compound excitation characteristics). This includes motors with compound excitation windings, low-power parallel excitation motors, and repulsive motors with damping windings.

(4) Electric motors with significant speed changes (series excitation characteristics). The speed increases rapidly during load shedding (for example, in a series excited motor).

According to the possibility of adjusting the speed, it can be divided into:

(1) A motor with only one speed.

(2) There are motors with multiple speeds (such as pole changing synchronous motors and pole changing asynchronous motors).

(3) Adjustable speed motor. The speed can be adjusted within a certain range, or the speed is almost completely constant (for example, for motors with weakened magnetic fields and parallel excitation), or the speed changes greatly (for example, for series excited motors or motors connected to the main current regulator).