A wind turbine is a device that converts kinetic energy of wind into mechanical energy. When mechanical energy is put to use directly in some equipment such as grinding stones or a pump, it is called a windmill. Instead, when it is converted to electricity for further use, the device is known as wind turbine or wind generator. Wind turbines are mounted at high elevation so as to receive a constant flow of wind power at higher average velocity. Usually, wind turbines need an average speed of 35 kilometer/hour or 11 meters/second. Wind velocity mapping is done before selecting a place for wind turbine. Higher the wind speeds, more are the chances to get continuous flow of electricity (Whitburn, 2012).
As terminology implies, 1- kW rated capacity wind turbine would generate theoretically maximum of 1 kW of power per hour, if continuous flow of wind with the average wind velocity is available at all the time; however, in all practical purposes it does not happen so because wind energy is intermittent. In the long run, wind turbines are found to generate electricity only at 10-40% of their rated capacity. This means that wind turbine with the rated capacity of 1 kW would generate between 2.4 kWh (1× 24× 0.10) and 9.6 kWh of power per day (1×24× 0.40) (Whitburn, 2012).
Wind turbines can be segregated on the basis of horizontal- and vertical-axis turbines. Horizontal-axis turbines have tail fins that keep blades facing the wind. A constant flow of wind keeps turning the rotor blades of the turbine, which is connected to the generator through a rotating shaft and gear-wheel assembly. ...Show more