Two dc series motor are mechanically coupled. One machine runs as motor and the other as generator. The iron losses of the two machines will be identical when

Q. Two dc series motor are mechanically coupled. One machine runs as motor and the other as generator. The iron losses of the two machines will be identical when

A.            Both have the same excitation

B.            Both have the same speed

C.            Both have the same back emf

D.            Both operate at the same voltage

Answer: Both have the same excitation