Question

Calculate the shaft power developed by a motor using the given data: Eb = 50V and I = 60 A. Assume frictional losses are 400 W and windage losses are 600 W.

(a) 4000 W

(b) 2000 W

(c) 1000 W

(d) 1500 W

This question was posed to me in an international level competition.

Question is from Dynamics in section Dynamics of Electrical Drives of Electric Drives

Answer 1

Right answer is (b) 2000 W

Explanation: Shaft power developed by the motor can be calculated using the formula P = Eb*I-(rotational losses) = 50*60 = 3000 – (600+400) = 2000 W. If rotational losses are neglected, the power developed becomes equal to the shaft power of the motor.