The maximum speed variation in a 3-phase synchronous motor is
A)10 per cent
B)6 per cent
C)4 per cent
D)zero

Question

Quizplus · Accepted Answer

The speed of a 3-phase synchronous motor is constant at a given frequency, regardless of the load, which means the speed variation is zero. This is because the speed is determined by the supply frequency and the number of poles in the motor, according to the formula $N_s = \frac{120f}{P}$, where $N_s$ is the synchronous speed, $f$ is the supply frequency, and $P$ is the number of poles.

The Maximum Speed Variation in a 3-Phase Synchronous Motor Is