Question

 

What is a difference between syncronous and asynconous machine?

 

Answer 1

What is a difference between Synchronous and Asynchronous machine?

(i) Synchronous motor is a machine whose rotor speed and the speed of stator magnetic field is equal.

Asynchronous motor is a machine whose rotor rotates at the speed less than the synchronous speed.

(ii) Synchronous motor does not have slip. The value of slip is zero.

Asynchronous motor has slip. Therefore, the value of slip is not equal to zero.

(iii) Synchronous motor is costly as compared to Asynchronous motor.

(iv) Efficiency of Synchronous motor is greater than Asynchronous motor.

(v) Synchronous motor is not self starting whereas Asynchronous motor is self starting.

(vi) Synchronous motor operates smoothly and relatively good at low speed that is below 300 rpm, whereas Asynchronous motor operates at high speed that is above 600 rpm.

(vii) Current is given to the rotor of synchronous motor whereas the rotor of Asynchronous motor does not require any current.

(viii) Change in applied voltage does not affect the torque of synchronous motor, whereas it affect the torque of Asynchronous motor.

One example of a synchronous motor is the "stepping motor" which widely used in applications that involve position control. One example of asynchronous motor is "Centrifugal Pump" which widely used in buildings for pumping the general water supply, as a booster and for domestic water supplies.