A 150 kW, 3000 V, 50 Hz, 6-pole star-connected induction motor has a starconnected slip-ring rotor with a transformation ratio of 3.6 (stator/rotor). The rotor resistance is 0.1 \Omega / \text { phase } and its per phase leakage inductance is 3.61 mH. The stator impedance may be neglected. Find (a) the starting current and torque on rated voltage with short-circuited slip-rings, and (b) the necessary external resistance to reduce the rated-voltage starting current to 30 A and the corresponding starting torque.