Wind turbines operate on a simple principle. The energy in the wind rotates the blades around a rotor. The rotor is connected to the main shaft, which spins a generator to create electricity. Wind turbines are initiated on a tower to take the most energy. At 30 meters or more above ground, they can take advantage of faster and less turbulent wind. Compare to early turbines were small by today’s standards, with the amount of 20-30 kW each. Since then, they have increased greatly in size delivering up to 7 MW.
Fig. 3.4 (a) onshore windmill
It is important to know how formed, that is due to variation of heat in the layers of atmosphere where the heat is produced from sun. where earth rotates heat various at these point wind is generated. The of wind depends on amount of sun lights ,the lesser the sun light, more the wind with less heat. The flow of wind will completely depends on the type of area, the types of land and the amount of plants are there in that region. Usually hill region produces lot of wind since its peak is high and now obstacles. Spreading the information to the readers who can understand theory of wind mill will be a better option because knowing the mechanical terms is important here to generate better electric power using wind mill.
Small wind facilities are used to provide electricity to isolated locations and utility companies increasingly buy back surplus electricity produced by small domestic wind turbines. A large wind farm may consist of hundreds of individual wind turbines which are connected to the electric power transmission network and can be located either in-land (onshore) or in bodies of water (offshore). Offshore wind farms can harness more frequent and powerful winds than are available to land-based installations.
Fig. 3.4 (b) offshore wind mill
There are various method that are tried with lastest wind mill to get better accuracy. Making an observation, even today generation uses only three blade pattern which are placed along with the rotor and swap.