Wind Power
Small wind-electric systems can provide electricity on remote, off-grid sites, or right in town connected to the utility grid. Wind-power systems can make economic and environmental sense. They also bring a great deal of satisfaction—there´s nothing quite like watching your wind generator convert a summer breeze or a winter storm into electrical energy.
How It Works
Boiled down to its simplest principles, a wind generators rotating blades convert the winds kinetic energy into rotational momentum in a shaft. The rotating shaft turns an alternator, which produces electricity.
The blades are engineered airfoils, matched to the alternator, that capture the winds energy. Most modern wind generators use three blades, the best compromise between the highest efficiency possible (one blade) and the balance that comes with multiple blades. Together, the blades and the hub or rotor, which is the collector of the system, intercepts the passing wind to produce rotation and thereby electricity.
In most small-scale designs, the rotor is connected directly to the shaft of a permanent magnet alternator, which creates AC power. The AC output is rectified to DC to either charge batteries or feed a grid-synchronous inverter.
The blades must turn to face the wind, so a yaw bearing is needed, allowing the wind turbine to track the winds as they shift direction. The tail directs the rotor into the wind. A governing system limits the rotor rpm as well as generator output to protect the turbine from high winds. A shutdown mechanism is also utilized to stop the machine when necessary, such as during an extreme storm, when you do not need the energy, or when you want to service the system.
