1. It is reliable and is of low requirements for maintenance and for it has no brush and commutator.
2. It is convenient for the stator winding cooling.
3. Small inertia improves the system efficiency.
4. Be adapt to high speed and high torque working state.
5. Be well used in ac servo mechanisms and computers for its rapid and accurate response characteristics.
6. Have small diameter and high resistance.
7. Servo motors are wound with two phases physically at right angles or in space quadrature and are featured with a fixed winding excited for a fixed voltage source.
8. For ac servo motor, power inputs at maximum fixed-phase excitation and at maximum control-phase signal are in balance. It is because that the servo motor windings are designed with the same voltage-turns ratio.
9. No matter at any speed, torque for an ideal servo motor is directly proportional to the servo motor's control-winding voltage.
10. With the ratings increasing, the inherent damping of servo motors decreases. Otherwise, the servo motors have a reasonable efficiency at the sacrifice of speed-torque linearity. Most larger servo motors have integral auxiliary blowers to maintain temperatures within safe operating ranges. Servo motors are available in power ratings from less than 1 to 750 W, in sizes ranging from 0.5 to 7.