Question

Which among the following is the example of Class B?

(a) Inorganic material with adhesives

(b) Hard fiber

(c) Wood

(d) Impregnated oil

This question was addressed to me during an interview.

I'm obligated to ask this question of Temperature Rise and Insulating Materials topic in chapter Electrical Engineering Materials of Design of Electrical Machines

Answer 1

Correct answer is (a) Inorganic material with adhesives

For explanation I would say: Impregnated oil is the example of Class H. Hard Fiber is the example of Class Y and Wood is the example of Class A.