Windmill fantail

The yaw system is a mechanism or a technical system to align the rotor of a horizontal axis wind turbine, a wind mill or a wind turbine against the wind. This can be done either by the force of the wind itself or by servo motors (also called azimuth drive motors or greed ), as is common for large wind turbines.

Adjustment by the wind

The alignment by the wind itself can called, for example by means of a simple wind vane for small plants or by an auxiliary wind turbine, side wheel or wind rose. The latter is common in Dutch Mills ( cap windmills ).

The axis of rotation of the side gear is disposed on the rotatable cap transverse to the axis of the mill of the main wind turbine, and drives a worm, which engages with teeth on the lower ring of the rotating rim, which carries the cap. If the side gear rotated by cross blowing wind, it is the transmission and thus the whole cap in motion. The self- locking of the gear to prevent frequent changes of direction.

The turntable is designed as a slip ring or roller slewing ring and protected by an apron from the weather. A multi-stage gear drive instead of worm gear allowed a more accessible, internal teeth of the ring gear.

Foreign force adjustment

Power- driven open systems determine the wind direction sensors, known as wind direction sensor, and control of electric servomotors. In order to avoid oscillations of the system around the vertical axis, usually several servomotors are braced against each other or the whole camp with a brake set when it is not in motion. When moving around the vertical axis strong resistance moments act ( centrifugal forces) one to the rotor and the rest of the structure. The Yaw modern wind turbines is therefore slow and heavily damped.

In the long run a permanent track of the wind direction would lead to cord connections twist to the tower. The system control if necessary, ensures untwisting. We can therefore now and then a plant " carousel ride " look, with a gondola rotation takes about 10 to 20 minutes. For this to be carried out at low wind or no wind, a mobility ranging from three to four nacelle turns.