Question

What is the dependency of the cost of the armature and field windings with respect to large number of poles?

(a) high cost for armature windings, low cost for field windings

(b) high cost for armature windings, high cost for field windings

(c) low cost for armature windings, high cost for field windings

(d) low cost for armature windings, low cost for field windings

This question was addressed to me by my college director while I was bunking the class.

This key question is from Selection of Number of Poles topic in portion Thermal Design Aspects of Electrical Machines & D.C of Design of Electrical Machines

Answer 1

Correct option is (d) low cost for armature windings, low cost for field windings

To explain I would say: With large number of poles the armature and the field windings reduce in number. Thus the cost of the field and armature windings also decrease.