Question

What is the formula for frequency of flux reversals?

(a) f = p*n

(b) f = p/n

(c) f = n/p

(d) f = (p*n)/2

This question was posed to me during an interview.

The doubt is from Selection of Number of Poles in section Thermal Design Aspects of Electrical Machines & D.C of Design of Electrical Machines

Answer 1

Correct answer is (d) f = (p*n)/2

The explanation is: Frequency is directly proportional to the number of poles (p). It is also proportional to the speed of the machine as well.