Question

What is the range of the pole length to pole pitch ratio for obtaining good power factor in induction motors?

(a) 1.5-2

(b) 1.3–1.8

(c) 1.0-1.25

(d) 1.1-1.6

I had been asked this question in an internship interview.

I'd like to ask this question from Separation of D and L, Standard Frames in chapter General Concepts and Constraints in Design of Rotating Machines of Design of Electrical Machines

Answer 1

Correct choice is (c) 1.0-1.25

For explanation: The range of the pole length to pole pitch ratio should be between 1.0-1.25 for the good power factor. The range of the pole length to pole pitch ratio should be between 1.5-2 for minimum cost.