A 50 Hz, 2-pole turbo generator is rated 200 MVA, 10 kV and has an inertia constant (H) of 10. Assume that the generator is synchronized with a large power system and has a zero accelerating power while delivering a power of 450 MW. Suddenly its input power is changed to 475 MW. Find the speed of the generator in r.p.m at the end of a period of 10 cycles. The rotational losses are assumed to be zero.