Answer / balakrishnan

servo motor-closed loop system where as induction motor is a
open loop system.

Answer / mustafa

Servo motors used to control speed systems.It varies the
field current applied to the generator which in turn
controls the speed of the motor connected.
Induction motor will work on synchronus speed .

Answer / narayan jaiswal

Servomotor is ac/dc motor controlled using servo-mechanism. It is negative feed-back controlled (closed loop) using position sensor. It does not rotate continuously but mostly upto 180 degrees. Its speed is reduced (torque increased) by gear mechanism. It is used when precise positioning is needed. General purpose DC servomotors are controlled by PWM signal. Pulse is repeated for every 20ms.

Induction motors rotate continuously as open loop system. There is no feed-back control.The speed may be varied but position cannot be controlled precisely.

Sir, plz tell me the relation b/w KW and frequency in Variable frequency Drive?

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