Question

Which of the following loss in a DC generator varies significantly with the load current?

(a) Field copper loss

(b) Windage loss

(c) Armature copper loss

(d) Cannot be determined

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

This interesting question is from Efficiency of DC Machine- 1 topic in division Efficiency and Testing of DC Machines

Answer 1

Correct answer is (c) Armature copper loss

For explanation: Armature copper loss is directly proportional to the square of armature current, as load current varies armature current varies, which is reflected significantly in loss as a square of it. Thus, armature copper loss can be detected.