Wind Turbine Info
The wind turbine is a rotating machine that converts kinetic energy in the wind (the energy of moving air molecules) into mechanical energy that later becomes electricity. The wind turbine also figures as: wind generator, wind power unit (WPU), wind energy converter (WEC), or aerogenerator. However, all the names stand for machinery consisting of:
- rotor (blades) which convert the wind's energy into rotational shaft energy;
- nacelle (enclosure) containing a drive train, usually including a gearbox and a generator;
- tower to support the rotor and drive train;
- electronic equipment such as controls, electrical cables, ground support equipment, and interconnection equipment.
The modern turbine towers are usually tubular and made of steel. Components subjected to repeated bending, such as rotor blades, may eventually develop cracks which eventually may lead to the component break. And because metal fatigue is a well known problem in the industry in general, this material is therefore usually not applied in rotor blades production. The most popular here would be fiberglass-reinforced polyester or wood-epoxy.
The size of typical wind generators may vary depending on its siting and practical application (residential, small businesses or industrial). The smallest turbines intended for homes or small businesses have rotor diameters of 8 meters or less, and would be mounted on towers of not more than 40 meters in height. Utility-scale turbines for based on land come in sizes of the rotor ranging from 50 meters to 90 meters, with towers of more or less the same size. The total height from the tower base to the tip of the rotor can reach approximately 135 meters.
Offshore turbines have much larger rotors, for it is easier to transport such large blades by ship than by land. At the moment, the biggest turbine of this kind is a 100-meter height and 150-meter bladespan Clipper's 7.5 megawatt MBE turbine (recently bought by the Queen of England for the Britannia Project.
There are two main types of wind turbines: horizontal and vertical-axis, from which the first one is most common nowadays. The only vertical axis turbine which has ever been manufactured commercially is Darrieus (named after the French engineer Georges Darrieus who designed it in 1931). The manufacturer was the U.S. company FloWind which went bankrupt in 1990's. This type of machine characterises with the C-shaped rotor blades which gives it a look similar to an eggbeater. There is normally two or three blades.