A three-phase asynchronous motor has 4 poles. The stator windings are star-connected and supplied by a voltage U = 380V (between phases), 50 Hz. the resistance between two terminals of the stator is 0.5 Q. The iron losses in the rotor are negligible. - At no-load, we obtained the following results: absorbed power P₂0 = 1200W, line current Io = 4 A. - At rated load, under the same voltage U = 380V, 50 Hz, we obtained the following results: The slip is 5%, the absorbed power is P₂ = 18 kW and the line current is I = 40 A. Calculate: 1- The stator Joule's losses at no-load (Piso). 2- The stator iron losses (p) knowing that the mechanical losses are 588W. 3- The synchronous speed (n.) and the rotor speed of rotation at load (n). 4- The frequency of the rotor current (f). 5- The stator Joule's losses (pjs). 6- The power transmitted to the rotor (P) and deduce the electromagnetic torque. 7- The rotor Joule's losses (pir). 8- The useful power (P) and deduce the efficiency of the motor.

A three-phase asynchronous motor has 4 poles. The stator windings are star-connected and supplied by a voltage U = 380V (between phases), 50 Hz. the resistance between two terminals of the stator is 0.5 Q. The iron losses in the rotor are negligible. - At no-load, we obtained the following results: absorbed power P₂0 = 1200W, line current Io = 4 A. - At rated load, under the same voltage U = 380V, 50 Hz, we obtained the following results: The slip is 5%, the absorbed power is P₂ = 18 kW and the line current is I = 40 A. Calculate: 1- The stator Joule's losses at no-load (Piso). 2- The stator iron losses (p) knowing that the mechanical losses are 588W. 3- The synchronous speed (n.) and the rotor speed of rotation at load (n). 4- The frequency of the rotor current (f). 5- The stator Joule's losses (pjs). 6- The power transmitted to the rotor (P) and deduce the electromagnetic torque. 7- The rotor Joule's losses (pir). 8- The useful power (P) and deduce the efficiency of the motor.

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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