Question

For a DC generator, given D = 0.35 m, L = 0.21 m, Coefficient of output = 108.5, efficiency = 0.9, speed = 1400 rpm. What is the output power of the DC generator?

(a) 65.12 W

(b) 72.35 KW

(c) 72.35 W

(d) 65.12 KW

I had been asked this question during an interview for a job.

My doubt is from Design of Output Equations in section Thermal Design Aspects of Electrical Machines & D.C of Design of Electrical Machines

Answer 1

Right answer is (b) 72.35 KW

Explanation: Generated power = 108.5 * 0.35 * 0.35 * 0.21 * (1400/60) = 65.12 KW

Output Power = Generated Power / Efficiency = 65.12 / 0.9 = 72.35 KW.