Three-Phase Squirrel-Cage Induction Motor
A three-phase, 60 Hz, squirrel-cage induction motor draws a current of 385 amps per phase and a total active power of 2344 kW when operating at full load from a 4000 volt (line) supply. The corresponding speed is 709.2 rev/min. The stator is star-connected and the resistance between two stator live terminals is 0.1 ohms. The machine has 10 poles, the total iron losses are 23.4 kW and the windage and friction losses are 12 kW.
(i) the power factor at full load,
(ii) the active power supplied to the rotor,
(iii) the total I2R losses in the rotor,
(iv) the load mechanical power and torque and the efficiency of the motor.
(v) Estimate the starting torque for the machine, making clear any assumptions that you make.