A 6-pole, 3-phase, 60-Hz induction motor takes 48 kW in power at 1140 rpm. The stator copper loss is 1.4 kW, stator core loss is 1.6 kW, and rotor mechanical losses are 1 kW. Find the motor efficiency.
The synchronous speed of an induction motor is 900 rpm. Under a blocked-rotor condition, the input power to the motor is 45 kW at 193.6 A. The stator resistance per phase is 0.2 ̣̉ and the transformation ratio is a = 2. Calculate (a) the ohmic value of the rotor resistance per phase and (b) the motor starting torque. The stator and rotor are wye-connected.
Note: a=1/K = (rotor Current/ stator current)