Question

What is the formula of the area of each end ring?

(a) area of each end ring =  0.32 * total cross section of rotor bars * number of poles

(b) area of each end ring =  0.32 / total cross section of rotor bars * number of poles

(c) area of each end ring =  0.32 * total cross section of rotor bars / number of poles

(d) area of each end ring =  1/0.32 * total cross section of rotor bars * number of poles

This question was posed to me at a job interview.

Query is from Design of Rotor in chapter Design of Single Phase Induction Motor of Design of Electrical Machines

Answer 1

Correct answer is (c) area of each end ring =  0.32 * total cross section of rotor bars / number of poles

The best I can explain: First the total cross section of rotor bars along with the number of poles are calculated. On substitution the area of each end ring is obtained.