Question

What is the range of frequency during the selection of number of poles?

(a) 20-50 Hz

(b) 25-40 Hz

(c) 25-50 Hz

(d) >50 Hz

This question was addressed to me by my school teacher while I was bunking the class.

Enquiry is from Selection of Number of Poles in chapter Thermal Design Aspects of Electrical Machines & D.C of Design of Electrical Machines

Answer 1

Right answer is (c) 25-50 Hz

To elaborate: While selecting the number of poles, the lowest value of frequency should be minimum 25 Hz. The highest value of frequency should be limited to 50 Hz.