rotor e mi 2. The power input to a 3-phase induction motor is 40 kW. The stator losses total 1 kW and the friction and winding losses total 2 kW. If the slip of the motor is 4%, find (a) the mechanical power output (b) the rotor Cu loss per phase and (c) the efficiency. 3. The rotor e.m.f. of a 3-phase, 440-V, 4-pole, 50-Hz induction motor makes 84 complete cycles per minute when the shaft torque is 203.5 newton-metres. Calculate the h.p. of the motor 4. The input to a 3-phase induction motor, is 65 kW and the stator loss is 1 kW. Find the total mechanical power developed and the rotor copper loss per phase if the ship is 3% Calculate also in terms of the mechanical power developed the input to the rotor when the motor yields full-load torque at half speed. 5. A 6-pole. 50-Hz, 8-phase induction motor, running on full-load, develops a useful torque of 162 N-m and it is observed that the rotor electromotive force makes 90 complete cycles per min, Calculate the shaft output. If the mechanical torque lost in friction be 13.5 Nm, find the copper loss in the rotor windings, the input to the motor and the efficiency. Stator losses total 750 W. 6. The power input to a 500-V, 50-Hz, 6-pole, 3-phase induction motor running at 975 rpm is 40 kW The stator losses are 1 kW and the friction and windage losses total 2 kW Calculate (a) the slip (b) the rotor copper loss (e) shaft output (d) the efficiency (a) 0.025 (6) 975 W (c) 36.1 kW (90%) 7. A6 pole. 3-phase induction motor develops a power of 22.38kW, including mechanical losses which total 1 492 kW at a speed of 950 rpm on 550 V, 50 Hz mains. The power factor is 0.88. Calculate for this load (a) the slip (h) the rotor copper loss (c) the total input if the stator losses are 2000 W (a) 0.05 (b) 1175 (c) 25.6 kW d) 82% (e) 30.4 A () 150] (d) the efficiency (e) the line current () the number of complete cycles of the rotor electromotive futce per minute.