# Induction Motor Power Problem

I have this textbook problem I am not sure how to go about doing it:

A 3 phase, 460V, 60HZ, 20KW induction Machine draws 25A at a power factor of 0.9 lagging when connected to an equivalent power supply. The core loss is 900W, stator copper loss is 1100W, Rotor Copper loss is 550W, Friction and Winding Loss is 300W. Calculate:

A) The air gap power B) The mechanical power developed C) The output horse power D) The efficiency

I calculated the Pelec to be 17927W and the pshaft is given as 20KW. Why is my power drawn lower than my output shaft power? I thought you had to subtract all the losses from pin to get the pout. I dont understand whether it is a motor or a generator, or how you would go about subtracting in the case of a generator.

• The answer hints that n<ns so im assuming its a motor? Then I don't get why Pin<Pout Nov 23, 2015 at 22:45
• Also would core losses be subtracted alongside stator core losses or rotational losses? Nov 23, 2015 at 22:48