Wind turbines or wind turbines are devices that convert wind energy into mechanical rotational energy. This makes a wind turbine different from a sail that uses wind energy directly, without conversion.
In the literature, you can often find the word "windmill" in relation to windmills. Indeed, windmills were the very first wind turbines to use the energy conversion principle.
Windmills have also been and are currently being used to lift water from wells and wells. Irrigation water lifts have small wind turbines. Water-lifting wind turbines for artesian wells can be quite impressive in size - their multi-blade wind wheels often reach several tens of meters in diameter.
Wind power plants are especially widespread. You've probably heard about the giant wind farms in Holland, which occupy entire fields and even go into the coastal zone of the sea. They consist of a large number of wind turbines with electric generators connected to a common network.
The principle of a wind farm is simple. The axle of the wind turbine is connected directly or through a transmission system to the axle of an electric generator (dynamo). The voltage removed from the generator is sent to the consumer's network or to charge the batteries.
Wind farms can be quite small, designed to supply electricity to a summer cottage or a private house. There are even mobile versions of such devices used in expeditions or hiking trips.
Wind turbine designs are very diverse. The horizontal axis windmill described above, often used in windmills, usually has two or more blades, but it can also consist of one equipped with a counterweight. Wind turbine blades are sometimes called wings or flaps. They can also differ in design. Even ancient windmills have flaps designed like a slotted wing. Some wind turbines have flexible blades, made according to the principle of a sail.
A wind turbine with a horizontal axis has a wind wheel, a mast on which it is mounted, and a tail. The latter turns the wind wheel with its axis along the wind. There are such installations without feathers (for example, with a vertical axis).
Vertical axis windmills are sometimes called windrotors. Their action is based on the difference in air resistance forces between concave and convex surfaces. It is interesting that the first such devices were used in the East as water lifters. Their rotor consisted of sails. Moreover, the tailwind filled and pushed the blades, and the counterwind folded, reducing their resistance.
The attraction of wind turbines is that they use free wind energy. Such devices do not pollute water and air with combustion products, do not consume oxygen. Therefore, they are considered as an alternative and environmentally friendly way to generate energy.
Wind turbines also have disadvantages. Large wind wheels pose a threat to birds. To obtain a large amount of electricity, it is required to use a large land area for a wind farm. The winds blow at a variable speed, which makes the energy received from the wind turbine unstable. The latter problem can be solved if part of the energy is used to charge the batteries.