Question

Which one is an example of variable loss?

(a) Windage loss

(b) Hysteresis loss

(c) Armature copper loss

(d) Friction loss

This question was posed to me in an internship interview.

I'd like to ask this question from Dynamics in portion Dynamics of Electrical Drives of Electric Drives

Answer 1

The correct answer is (c) Armature copper loss

To explain: Armature copper losses are variable losses as they depend on armature current which further depends on load. As load changes armature current changes hence armature copper losses (I^2 * r) also changes.