|How a standard wind turbine works, and its components
Measures the wind speed and transmits wind speed data to the controller.
Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
A disc brake, which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at
about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations
per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear
box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at
lower rotational speeds and don't need gear boxes.
Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
Drives the generator.
The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator,
controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician
to stand inside while working.
Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to
The blades and the hub together are called the rotor.
Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers
enable turbines to capture more energy and generate more electricity.
This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind",
facing away from the wind.
Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction
changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Powers the yaw drive.