Question

Which of the following is not the effect of iron loss?

(a) Loss of efficiency

(b) Excessive heating of core

(c) Increase in terminal voltage

(d) Rise in temperature of ventilating air

The question was posed to me by my college professor while I was bunking the class.

My question is taken from Efficiency of DC Machine- 1 topic in division Efficiency and Testing of DC Machines

Answer 1

Correct choice is (c) Increase in terminal voltage

For explanation: Iron loss causes excessive heat production in the core of a machine, which will rise the temperature of ventilating air, as it acts as heat exchanger. Thus, terminal voltage rise is not an effect of any loss.