Question

What is the formula for the copper area of the field windings?

(a) copper area = full load field mmf * current density in the field winding

(b) copper area = full load field mmf / current density in the field winding

(c) copper area = full load field mmf + current density in the field winding

(d) copper area = full load field mmf – current density in the field winding

I have been asked this question in examination.

The origin of the question is Design of Rotor topic in chapter Design of Synchronous Machines of Design of Electrical Machines

Answer 1

Correct option is (b) copper area = full load field mmf / current density in the field winding

The explanation: For the calculation of the copper area, first the current density in the field winding is calculated. Next the full load field mmf is calculated and the ratio gives the copper area of field windings.