Question

What is the value of ratio of gross core area to the area of circumscribing circle in stepped cores?

(a) 0.71

(b) 0.79

(c) 0.89

(d) 0.91

I got this question by my college professor while I was bunking the class.

Query is from Design of Core and Winding topic in portion Design of Transformers of Design of Electrical Machines

Answer 1

The correct choice is (b) 0.79

To explain I would say: 0.71 is the ratio of net core area to the area of circumscribing circle in stepped cores. The gross core area for stepped cores is 0.618 * d^2.