| These are advertised as "typhoon resistant". Like all big wind turbines, the props are variable pitch, feather under excessive wind, and rotation stops. The big trouble spot is the gearbox and its bearings.[1] These big turbines are advertised as "semi direct drive" turbines, which means they only have one stage of geared speed step-up. Large wind turbines are very slow compared to desirable generator RPMs, and the bigger the turbine, the lower the RPMs. Bearing trouble is currently the big limitation on turbine life. Not many large wind turbine drivetrains are reaching the 25 year design life. Huge bearings and gears with off-axis loads have problems not seen in other applications. As the wind changes, stresses appear from odd angles. This causes minor bearing damage, which increases wear, which eventually causes major damage. A new research result: [2][3] Argonne National Lab has been able to reproduce this problem in a benchtop setup. The metallurgy/lubrication problem is still not fully understood, and it's getting considerable attention. Stuff like this is the difference between a prototype and a long-lived production product. [1] https://www.stle.org/files/TLTArchives/2020/08_August/Featur... [2] https://www.energy.gov/eere/wind/articles/zeroing-no-1-cause... [3] https://www.sciencedirect.com/science/article/abs/pii/S09215... |
(Picture two flat-topped letter 'A's, one behind the other, with a crossbar going from the top of the front one to the top of the back one. The blades spin around this crossbar, an axle. The generator can be at one end of this axle, or in the blade hub. The whole structure is floating, moored at one corner, and can rotate to keep the blades facing into the wind as required.)