A 3-phase, 3.3 kV, 50 Hz, 10-pole, star connected induction motor has a no-load magnetizing current of 45 A and a core-loss of 35 kW. The stator and referred rotor standstill leakage impedances are respectively (0.2 + j 1.8) and (0.45 + j 1.8) Ω/phase. The motor is supplied from 3.3-kV mains through a line of reac tance 0.5 W/phase. Use approximate circuit model.
(a) The motor is running at 0.03 slip. Estimate the gross torque, stator current and power factor. Assume voltage at motor terminals to be 3.3 kV.
(b) Calculate the starting torque and current when the motor is switched on direct to line with voltage at far end of the line being 3.3 kV.