AC SERVO MOTOR

WHAT IS A SERVO MOTOR ?

• Servo Motor is also known as a Control Motor.
• They are used in Feedback Control Systems but not used for continuous energy conversion.
• The Principle of Servo Motor is similar to that of other electromagnetic Motors but the Construction and Operation are different.
• Power rating varies from fraction of watt to hundreds of watts.

BLOCK DIAGRAM OF AC SERVO MOTOR

• Like wise in all other control systems,the input is passed through the Amplifier and then through the Servo Motor and if the output obtained is desirable the there is not use of the feedback loop.
• If the output Obtained is not desirable then the error in the output is fed back to the error detector and then through the Amplifier,as the error is very minute it is to be amplified and the given to the Servo motor.

CLASSIFICATION OF SERVO MOTORS

AC SERVO MOTOR CONSTRUCTION

              (i)Stator (ii) Rotor

Stator has two Distributed Windings with a displacement of 90  ̊̊ Electrical.

One winding is called Main or Reference winding and is excited by a constant AC voltage.

The other winding is called control winding and is excited by variable control voltage of the same frequency as that of the Reference winding.