By which of the following methods the constant speed of a synchronous motor can be changed to new fixed value ?
A)By changing the supply frequency
B)By interchanging any two phases
C)By changing the applied voltage
D)By changing the load.

Question

Quizplus · Accepted Answer

The speed of a synchronous motor is determined by the supply frequency and the number of poles in the motor, according to the formula $Speed = \frac{Frequency}{Number\ of\ Poles}$. Changing the supply frequency is the only method listed that can change the motor's speed to a new fixed value. Interchanging phases, changing the applied voltage, or changing the load does not affect the speed of a synchronous motor.

By Which of the Following Methods the Constant Speed of a Synchronous