It’s not the rpm that govern Hz output.  It’s the poles in the rotor times the rpm, come on.  You’re filming on top of a windmill as if you’re an expert....,(reply>), Pole pairs times the rpm/60 = grid frequency to be exact and that is only for grid-tied synchronous generators. There is also research of how to use wind turbines' kinetic energy with power converters' control for frequency support (synthetic inertia, deloading techniques (over-speeding, pitch control)). Sorry, I had a need to be a smartass for a minute.