The stator resistance, stator-referred rotor resistance and equivalent inductive reactance of a 400 V, 4-pole, 50 Hz, Y-connected induction motor are 0.22 Q, 0.25 Q and 3.5 Q, respectively. The motor is driving a constant load torque of 45 Nm at 1410 RPM. Calculate the motor speed and starting current if the supply frequency is reduced to 42 Hz. Compare and comment on the starting currents before and after the frequency is reduced. Assume that the rotational losses are negligible.

The stator resistance, stator-referred rotor resistance and equivalent inductive reactance of a 400 V, 4-pole, 50 Hz, Y-connected induction motor are 0.22 Q, 0.25 Q and 3.5 Q, respectively. The motor is driving a constant load torque of 45 Nm at 1410 RPM. Calculate the motor speed and starting current if the supply frequency is reduced to 42 Hz. Compare and comment on the starting currents before and after the frequency is reduced. Assume that the rotational losses are negligible.

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter35: Harmonics 916

Section: Chapter Questions

Problem 3RQ: Would a positive-rotating harmonic or a negative-rotating harmonic be more harmful to an induction...

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