The rotor resistance and standstill reactance of a 3-phase induction motor are 0.015 Q and reactance 0.09 0 per phase. (i) What is the p.f. of the motor at start? (ii) What is the p.f. at a slip of 4 per cent? (iii) If the number of poles is 4, the supply frequency is 50-Hz and the standstill e.m.f. per rotor phase is 110 V, find out the full-load torque. Take the full-load slip as 4 per cent.

The rotor resistance and standstill reactance of a 3-phase induction motor are 0.015 Q and reactance 0.09 0 per phase. (i) What is the p.f. of the motor at start? (ii) What is the p.f. at a slip of 4 per cent? (iii) If the number of poles is 4, the supply frequency is 50-Hz and the standstill e.m.f. per rotor phase is 110 V, find out the full-load torque. Take the full-load slip as 4 per cent.

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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