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Q3). A 10KW, 415V, 50Hz, 4 pole, Y (star)-connected induction motor is running at 1425 rpm...

Q3). A 10KW, 415V, 50Hz, 4 pole, Y (star)-connected induction motor is running at 1425 rpm and is delivering full load output while operating at 89% efficiency.

a) Find the total losses of the motor [4 marks]

b) If the Copper loss, Core loss and Rotational loss are at a ratio of 1:0.7:0.2, find each loss separately [6 marks]

c) What is the torque output of the motor? [4 marks]

d) If the full load power factor is 0.85, what is the current drawn by the motor? [4 marks]

e) Find the phase voltage and phase current of the motor? [6 marks]

f) Find the full load slip of the motor? What will be running speed of the motor if the frequency is changed to 40 Hz assuming the operating slip remains the same? [6 marks]

g) Find the running cost of the motor for a year if the duty is 50% and cost of electricity is 30c per unit [4 marks]

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