Question

What should be the range of the field mmf to armature mmf ratio at full load?

(a) 1.0-1.2

(b) 1.1-1.3

(c) 1.3-1.5

(d) 1.1-1.25

I had been asked this question in quiz.

My question is taken from Pole Design topic in portion Thermal Design Aspects of Electrical Machines & D.C of Design of Electrical Machines

Answer 1

Right choice is (d) 1.1-1.25

To explain: The minimum value of the ratio should be atleast 1.1. The maximum value of the ratio should be not greater than 1.25.