Why slowdown Wind turbines/Max speed? isn’t it good for it to go faster? since the wind speed is a cubic?
funcition in the power output, so faster wind means alot more electricity yet i keep seeing articles trying to keep wind turbines from going too fast. why? do generators have limits?
Windmills are designed to work efficiently in relatively low wind speeds (or average wind speeds) so they will produce more continuous energy. For this reason, blades are very critically designed so that they are as light as possible to keep their inertia low so they will react to the low wind velocity. The air foils are designed for an ultimate wind speed much as aircraft are designed and rated with a never-to-exceed-velocity or Vne.
When wind speed significantly exceeds the aerfoil design, oscillations or "flutter" can be induced which will tear the blades apart. High shaft speeds and some inherent imbalances will induce vibration and also result in structural failure. The centrifugal forces of the extremely long blades, at higher than design rpm, will also destroy the wind generator.
Wind generators could be designed for high speed wind, but they would be much smaller and heavier and would either not be efficient or would not function at all in the average wind velocities.
4 Comments »
scottsdalehigh64 said :
July 1, 2009 at 9:35 pm
The point that you are making is that for any given generator, the power output is proportional to the cube of the wind velocity. However there are problems with high speed wind generators including stress on the machine as well as death of migratory birds. Slower but larger wind turbines are more efficient, especially in terms of land use.
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Brad said :
July 1, 2009 at 9:44 pm
Because they can self destruct and blow to pieces.
References :
mike1942f said :
July 1, 2009 at 9:45 pm
A wind mill built like a farm water pumping mill which has lots of blades for maximum torque, would produce turbulence between the blades - moving faster would have more turbulence. So to avoid that you use fewer blades and make them longer. But longer blades have greater variation in speed across their length (slower tangent speed in center, faster at tip) requiring more complicated calculations of shape. And if the blade gets long enough and the speed gets high enough, the tip can go supersonic - making a lot more noise and strain.
More importantly, it is the cube of the wind speed, not the blade speed and most of the time the wind is fairly low so the unit has to be designed to produce the most electricity at the average speed and thus may have to be shut down (feathered blades) if the wind gets too high to keep it from being destroyed.
References :
Rouse said :
July 1, 2009 at 10:48 pm
Windmills are designed to work efficiently in relatively low wind speeds (or average wind speeds) so they will produce more continuous energy. For this reason, blades are very critically designed so that they are as light as possible to keep their inertia low so they will react to the low wind velocity. The air foils are designed for an ultimate wind speed much as aircraft are designed and rated with a never-to-exceed-velocity or Vne.
When wind speed significantly exceeds the aerfoil design, oscillations or "flutter" can be induced which will tear the blades apart. High shaft speeds and some inherent imbalances will induce vibration and also result in structural failure. The centrifugal forces of the extremely long blades, at higher than design rpm, will also destroy the wind generator.
Wind generators could be designed for high speed wind, but they would be much smaller and heavier and would either not be efficient or would not function at all in the average wind velocities.
References :
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