Wind Power Nuts and bolts
Small wind-power systems can supply electricity on isolated, off-grid sites, or directly in town connected to the power grid. Although wind systems have need of more maintenance and need even more attention than solar-electric or microhydro-power systems, if you invest up front in good quality equipment, design, and installation, wind-energy systems can make economic and environmental sense. They also produce a great deal of fulfillment-theres nothing quite like watching your wind generator change a summer breeze or a winter storm into electrical energy.
How It Works
Boiled down to its simplest principles, a wind generators revolving blades transfer the winds kinetic energy into rotational momentum in a shaft. The turning shaft turns an alternator, which produces electricity. This electricity is passed through wiring along the tower to its end use.
The blades use engineered airfoils, matched to the alternator, that catch the winds force. Nearly all new wind generators make use of three blades, the best compromise between the maximum efficiency possible (one blade) and the equilibrium that comes with several rotors. Together, the blades and the hub they are attached to are termed the rotor, which is the collector of the system, catching winds that pass by. Most turbines on the market these days are upwind machines-their blades are on the windward face of the tower. A few downwind machines are offered, but neither configuration has a clear working advantage over the other.
In most small-scale designs, the rotor is fixed directly to the shank of a permanent magnet alternator, which creates rough, three-phase AC. Rowdy, three-phase electricity means that the voltage and frequency change continuously with the wind speed. They are not set like the 60 Hz, 120 VAC electricity coming out of ordinary household outlets. The wild production is rectified to DC to either charge batteries or supply a grid-synchronous inverter. In nearly all designs (up to 15 KW in peak capacity), the rotor is as a rule connected directly to the alternator, which eliminates the added maintenance of gears. In systems 20 KW and bigger, as well as a few smaller wind systems (like the Endurance, Tulipo, or Aircon), a gearbox is used to step up alternator speed from a slower revolving rotor.
The blades have got to turn to meet the wind, so a yaw bearing is required, allowing the wind turbine to follow the winds as they change course. The tail directs the rotor into the wind. Some variety of governing system limits the rotor rpm as well as generator output to guard the turbine from excessive winds. A shutdown mechanism is also useful to halt the unit when necessary, such as for the duration of an extreme storm, when you do not need the power, or at which time you wish to repair the system.
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Sol Green is a family man who believes that we can protect the environment by utilizing alternative energies that are clean as in solar and wind power.