Question

1. A 15 hp, 4 pole, 208 V, 60 Hz, Y-connected, three-phase squirrel cage induction motor has the following parameters in Ω/phase referred to the stator: R,-0.220, Xi = 0.430, X,-15.0, R2 0.130 and X2-0.430. Mechanical and core losses amount to 300 W and 200 W respectively for rated voltage. (a) The motor is fed with a 60 Hz, 208 V voltage. It runs with a slip of 4.5 %. Find the speed, shaft torque and power, efficiency and power factor. Compute current and reactive power absorbed by the motor. Draw the approximate torque/speed curve, showing the synchronous speed and running speed Give the starting current and torque in pu value. Ignore the magnetizing branch. frequency. (b) For a motor initially at standstill, find the starting shaft torque, current and power factor. (c) Calculate the pullout torque developed by this motor when supplied with rated voltage and

Answer 1

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