Why wind turbines need those troublesome gearboxes 

Thank You for the great video and information. I would love to learn a lot more about these gearboxes. Gives me a lot to think about. Again Thank You

thanks for the video. It really helped me

The first illustration showed a sun gear with 10 teeth. the planetary gears had 25 teeth. I calculated, that the ring gear has 60 teeth, giving that planetary set a 7:1 gear ratio. the second illustration looked like it could be 4:1 as described by the narrator. I couldn't count the teeth of any two elements, to calculate the third, because the planetaries were pictured in the carrier. I, myself, would like to see a 2 stage planetary transmission, with the second sun gear directly fitted to the rotor shaft of the alternator. I prefer asynchronous alternators, because that slight slip loss protects the transmission from wind gusts, and dampens torsional oscillations. They aren't limited by the field strength of permanent magnets, so they can control the rotors in adverse wind conditions. If the field strength of permanent magnets is exceeded, the alternator rotor just skips over the stator poles, and basically free-wheels. That's a disaster, if the blades can't be feathered out in time. If the stator isn't disconnected from the grid, the enormous opposing magnetic fields can weaken or degauss the magnets, effectively destroying the alternator. Induction, while less efficient, is much more fault tolerant.

I think you need to take some time and go to inplix website to learn how to make it.