Small Wind System Components
Small wind turbines usually consist of the following components:
- Rotor – This consists of the blades and a shaft. The blades are usually fiberglass, metal, or reinforced plastic or wood. The wind flows over the blades and converts the kinetic energy from moving wind into rotational motion of the rotor. The diameter of the circle formed by the rotor blades determines how much energy can be extracted from the wind and thus the power generated by the system.
- Generator/Alternator – This produces electricity from the rotation of the turbine rotor. A generator produces Direct Current (DC) power or an alternator produces Alternating Current (AC) power, depending on the application for the turbine.
- Gearbox (on some) – Most turbines above 10 kW use a gearbox to match the rotor speed to that of the generator.
- Nacelle – This is the removable casing to protect the generator/alternator and gearbox.
- Tail vane (Yaw system) – A yaw system aligns a HAWT with the wind. Most micro and mini systems use a simple tail vane that directs the rotor into the wind. In some systems, the rotor is downwind of the generator, so it naturally aligns with the wind. Some yaw systems can be offset from the vertical axis to regulate rotor power and speed by tilting the turbine slightly upward.
The following components are also usually supplied as part of a small wind turbine package:
- Control & Protection System – Control systems vary from simple switches, fuses and battery charge regulators to computerized systems for control of yaw systems and brakes. The sophistication of the control and protection system varies depending on the application of the wind turbine and the energy system it supports.
- Tower – The tower holds the turbine in the path of the wind and is therefore an integral part of a wind energy system. It must be designed to support adverse conditions, such as extreme winds, hail and icing. For information on tower height, see Your Turbine Site. Several types of towers are available:
- Tilt-up towers (sometimes called "pipe" towers) are usually only used for systems under 1,000 W as they allow assembly of the turbine on the ground and allow safe and convenient maintenance of the turbine. These towers are usually erected by a winch or heavy vehicle and are usually not supported by guy-wires. See first photo below, courtesy of the American Wind Energy Association (AWEA).
- Guyed towers are economical, very strong when properly installed, and are also usually tilt-up. The guy wires require space around the base of the tower so they can be properly anchored. See second photo below, courtesy of TRUE-NORTH Power Systems.
- Non-Tilt-up, self-supporting towers are usually lattice or cylindrical in shape and are generally used for turbines above 50 kW. They are very strong, more expensive, and often require a crane to erect. See third photo (courtesy of AWEA) and fourth photo (courtesy of Yukon Energy Corporation) below.