Synchronous motors can be divided into permanent magnet synchronous motors, hysteresis synchronous motors, and reluctance synchronous motors based on the different magnetic fields. Asynchronous motors include induction type and AC commutator type, among which induction type asynchronous motors can be further divided into three-phase asynchronous motors and shield pole asynchronous motors.

The main function of an electric motor is to convert electrical energy into mechanical energy to drive various mechanical devices, while a generator converts other forms of energy, such as chemical energy, water energy, or wind energy, into mechanical energy first, and then converts mechanical energy into electrical energy.