A 3-phase induction motor has a 4-pole, star-connected stator winding and runs on 50 Hz with 400 V between lines. The rotor resistance and standstill reactance per phase are 0.4 Ω and 3.6 Ω respectively. The effective ratio of rotor to stator turns is 0.67. Calculate (a) the gross torque at 4% slip;
(b) the gross mechanical power at 4% slip;
(c) maximum torque,
(d) speed at maximum torque; and
(e) maximum mechanical power output (gross). Neglect stator impedance.