A three-phase, 480-V, 60-Hz, 6-pole, Y-connected induction motor has its speed controlled by slip power. The circuit parameters are given: Rs=0.06 ohms, Rr=0.05 ohms, Xs=0.2 ohms, Xr=0.3 ohms and Xm=6 ohms. The turn ratio of the rotor to stator winding is n=0.8. The no-load losses of the motor are equal to 150 W. The rotor and stator cupper losses are equal to 249.21 W. The slip power losses are estimated to 8000W. The load torque is 173.61 N.m. at 700 rpm. The efficiency is equal to: Select one: a. 71.5% b. None of these c. 81.5% d. 91.5%

A three-phase, 480-V, 60-Hz, 6-pole, Y-connected induction motor has its speed controlled by slip power. The circuit parameters are given: Rs=0.06 ohms, Rr=0.05 ohms, Xs=0.2 ohms, Xr=0.3 ohms and Xm=6 ohms. The turn ratio of the rotor to stator winding is n=0.8. The no-load losses of the motor are equal to 150 W. The rotor and stator cupper losses are equal to 249.21 W. The slip power losses are estimated to 8000W. The load torque is 173.61 N.m. at 700 rpm. The efficiency is equal to: Select one: a. 71.5% b. None of these c. 81.5% d. 91.5%

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter32: Three-phase Motors

Section: Chapter Questions

Problem 6RQ: Name three factors that determine the torque produced by an induction motor.

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