In the following, the other components of a wind turbine, being not part of the chapters before, are presented. They include (1) systems to track wind directions, (2) cooling and heating elements, (3) lightning protection equipment, (4) cranes and elevators, and finally (5) fire extinguishing equipment.
The purpose of these components is to turn the turbine's rotor into the wind at an optimal angle. Generally, information measured by the weather station is used to determine the direction of the wind.
In general, a distinction is made between passive and active systems in horizontal axis wind turbines (HAWTs):
Passive systems do not need electric yaw drives.
Turbines whose rotors are behind the tower (downwind) follow the wind automatically, while upwind turbines have weather vanes.
Weather vanes are well known parts of the windmills used historically in the United States to pump water; here, the direction of the wind is determined in a very simple fashion.
The additional loads and the forces that occur when the direction of the wind changes suddenly mean that passive wind tracking systems are only used with wind turbines whose rotor diameter does not exceed approx. 10 meters.
Active systems. These systems are used both on upwind and downwind rotors. Here, a drive (actively) rotates the nacelle on the tower. Such active systems ("rosettes") were already used in the late 18th century in Dutch windmills.
Nowadays, azimuth motors (also called yaw drives) are most commonly used, either singly or as multiple motors at a time. A weather vane on the nacelle provides information to the azimuth drive. The motors are on the azimuth ring, which slides the nacelle into its optimal position when driven by the motors.
Azimut drive. © Bundesverband WindEnergie e.V.
The temperatures inside a nacelle can be quite high due to the waste heat from the gearbox and the generator. Special ventilators are therefore installed in the nacelle to keep it cool.
In addition, there are usually special cooling units for the individual components of a wind turbine, such as the gearbox.
During the winter, temperatures often fall below freezing where wind turbines are set up. When the oil in the gearbox freezes, it is hard to get the system running again after it has been motionless for some time. Therefore, heaters are often used to warm up the oil in the gearbox.
In addition, rotor blades are also heated to prevent them from icing over or being damaged by condensed water.
Finally, anemometers and weather vanes also have to be heated in cold regions to prevent them from malfunctioning and damaging the turbine.
Wind turbines are tall structures that are generally exposed and therefore vulnerable to lightening. Lightening often strikes the tips of rotor blades.
The following solutions are available to absorb lightening:
The current is then passed along inside the rotor blade along metal conductors and then over the nacelle before being directed down the tower to the ground anchor. Especially sensitive areas are avoided.
Most wind turbines contain winches to haul small spare parts and tools into the nacelle. Inside the nacelle, swinging crane and gantry cranes are used.
Fire extinguishers are also provided within wind turbines to combat any fire that may occur in the hardware or electronics.
Often, the fire extinguishers are manual tanks, but automatic fire detection and extinguishing systems are also used.