Wind turbines today are discovered another time, because they can produce high quantity of energy from wind. In the last ten years, turbines have been used more than past, because technology develop is so high.
Odiern technology applied to wind turbines permits men to build more efficient turbines than past; these methods to produce more energy are:
UPWIND WINDMILLS
This turbines have a great advantage, in fact wind doesn't pass in the area of shade of windmill tower; in opposition, blades and rotor must be placed in a certain distance from tower, otherwise wind energy is drammatically reduced. In this case, rotor isn't flexible, because wind is always captured. An example of upwind turbine is:
DOWNWIND WINDMILLS
Rotor is placed to high to tower and the structure can follow passively wind direction. In this case, windmill needs electric cables to carry electric energy and, in consequence, user is warned with a method called Cable Twist Counter that indicates that cables are twisted. Now the rotor is flexible, in fact blades can bended themself and be proofed to wind energy; also all the structure is lighter than upwind windmills, but fluttuation is major than before and the tower must be more resistance. An example is:
An important method applied to upwind windmills is called YAW MECHANISM and consist to rotate rotor and blades following wind direction. At the base of tower, inside, there are driving gear and brakes as showed in the last picture showed:
This is a sample immage that shows what is Yaw Mechanism:
This heavy structure needs high quantity of energy to rotate: for this reason, if wind direction changes a little, windmill isn't rotate and the difference between wind direction and windmill direction is called yaw error.
Today wind turbines had various dimension: the greatest was built in Hawaii and has blades as long as a football field, 20 times higher than old windmills and it can produce electric energy sufficient for 1400 houses. Usually rotor varyes from 245 cm to 760 cm, and are high from 12 m to 17. Modern windmills have a security system: when wind speed is high, system management activates a brake or rotate windmill in a position opposing wind direction. For example, look at these pictures:
Wind turbines work very well: look at these charts that represent energy production:
Energy produced is very high and has an exponential increase. Moreover, if you think that there're more than 10 wind turbines in a valley to produce energy ...
