Question

Which of the following equations represents the RMS value of the generated EMF in a short-pitched N-turn armature coil of an AC machine ____________

(a) E = √2πkpfrNΦ

(b) E = 2πkpfrNΦ

(c) E = NΦωrkpsinωrt

(d) None of the mentioned

I had been asked this question during an internship interview.

Enquiry is from Generated EMF in portion Principles of Electro mechanical Energy Conversions of Electrical Machines

Answer 1

Right option is (a) E = √2πkpfrNΦ

Best explanation: EMF induced = NΦωrkpsinωrt,

Emax = NΦωrkp when sinωrt = 1

RMS value, E = Emax/√2 = √2πfrkpNΦ