د علي جعفر مهدي الحسيني

A460-V. 25-hp. 60-Hz. four-pole. Y-cOIlllected wOlUld-rotor induction
motor has the following impedances in ohms per phase referred to the stator circuit:
Rl = 0.641 0
Xl = 1.106 0
R2 = 0.3320
X2 = 0.4640 XM = 26.3 0
(a) What is the maximrun torque of this motor? At what speed and slip does it
occur?
(b) What is the starting torque of this motor?
(c) When the rotor resistance is doubled. what is the speed at which the maximum
torque now occurs? What is the new starting torque of the motor?
(d) Calculate and plot the torque-speed characteristics of this motor both with the
original rotor resistance and with the rotor resistance doubled.