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Q4 (a) A 3-phase induction motor having a synchronous speed of 1200rpm draws 80kW from a...

Q4 (a) A 3-phase induction motor having a synchronous speed of 1200rpm draws 80kW from a 3-phase feeder. The copper losses and core losses in the stator amount to 5kW. If the motor runs at 1152rpm, calculate:

(i) the rotor input power;

(ii) the rotor copper losses;

(iii) the gross mechanical power output;

(iv) the net mechanical power with knowing that the windage and friction losses are 2kW;

(v) the efficiency of the motor

(b) Compare the brushed motor (DC motor) and a brushless motor (Induction Motor) in FIVE aspects.

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