Question

How can the variation in ratings be obtained?

(a) alternative windings

(b) alternative core lengths

(c) alternative pole pitch

(d) alternative pole length

I had been asked this question during an internship interview.

This intriguing question originated from Separation of D and L, Standard Frames topic in division General Concepts and Constraints in Design of Rotating Machines of Design of Electrical Machines

Answer 1

Correct choice is (b) alternative core lengths

Explanation: The frame is a mechanical structure required to house a stator of given outside diameter, housing the bearings, end covers, terminal box and maximum length. The variation in the ratings can be obtained using alternative core lengths.