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(5) A 3-phase 346-V 50-Hz 6-pole star-connected slip-ring induction motor has the stator impedance of (0.8+j1.9) 92/phase, rotor impedance referred to stator of (1.2+j2.1) 02/phase and magnetising reactance of 40 2/phase. Ignoring the no- load losses and using the approximate equivalent circuit, calculate the (a) plugging torque at a speed of 950 rpm, (b) output current and power factor when operating as an induction generator at 1100 1pm. Suppose, in motor operation, balanced external rotor resistors have been added to effect maximum starting torque. With these resistors retained in the rotor circuit, find the mechanical power and efficiency at a speed of 700 rpm. (39.1 Nm, 19.1 A, 0.83 leading, 5.1 kW, 66.1%