The servo motor is also called as the electric motor. In the automatic control system, it is used as an actuator. It converts the received electric signal into angular displacement or angular velocity output on the motor shaft. It is divided into two major categories of DC and AC servo motors. AC servo motor It is divided into asynchronous servo motor and synchronous servo motor.
In the field of servo and speed control, AC systems are gradually replacing DC systems. Compared with the DC system, the AC servo motor has the advantages of high reliability, good heat dissipation, small moment of inertia, and the ability to work under high pressure conditions. Because there is no brush and steering gear, the AC server system has become a brushless servo system. The motors used therein are brushless cage induction motors and permanent magnet synchronous motors.