Electronics and Communication Engineering - Power Electronics - Discussion

Discussion Forum : Power Electronics - Section 3 (Q.No. 9)

Power Electronics

A 3 phase induction motor is controlled by voltage and frequency control such that the ratio V/f is constant. At 50 Hz, the speed is 1440 rpm. At 25 Hz, the speed is likely to be

about 1350 rpm

about 720 rpm

about 360 rpm

either (b) or (c)

Answer: Option

Explanation:

In this case synchronous speed at 50 Hz is 1500 rpm. Therefore synchronous speed at 25 Hz is 750 rpm. Since slip is about 3 - 5%, speed is about 720 rpm.