. A six pole generator with fixed field excitation developes an emf of 100 V
when operating at 1500 rpm. At what speed must it rotate to develop 120 V?
(a) 1200 rpm
(b) 1800 rpm
(c) 1500 rpm
(d) 400 rpm
Solution: The emf induced is directly proportional to rate at which flux is intercepted which varies directly as the speed of rotation of the generator.
New speed = 120/100 x 1500 rpm
= 1800 rpm