AC Servo systems are typically permanent magnet synchronous motors that often have low torque-to-inertia ratios for high acceleration ratings. AC servo motors have an output shaft that can be positioned by sending a coded signal to the motor. As the input to the motor changes, the angular position of the output shaft changes as well. Generally, AC servo motors are small but powerful for their size and easy to control. Induction and gearmotor types are some common forms of AC servo motors.
