Question

How many number of poles should be used for large motors of relatively low speed?

(a) should be equal to 2

(b) should be lesser than 2

(c) should be greater than 2

(d) should be more than 4

I had been asked this question by my college director while I was bunking the class.

Enquiry is from Design Steps and Considerations in division Design of Permanent Magnet (PM) DC Motors of Design of Electrical Machines

Answer 1

Correct answer is (c) should be greater than 2

To elaborate: The number of poles should be greater than 2 for large motors with relatively low speed. The number of poles is equal to 2 for small motors.