Engine room: the engine room contains the key equipment of wind turbine, including gearbox and generator. Maintenance personnel can enter the engine room through the wind turbine tower. The left end of the engine room is the rotor of the wind turbine, namely the rotor blade and shaft.

Rotor blade: capture the wind and transmit it to the rotor axis. On modern 600 kW wind turbines, each rotor blade measures about 20 meters in length and is designed to resemble the wing of an airplane.

Axis: the rotor axis is attached to the low-speed shaft of wind turbine.

Low speed shaft: the low speed shaft of wind turbine connects the rotor shaft and gearbox together. On modern 600 kW wind turbines, the rotor speed is quite slow, about 19 to 30 rpm. The shaft has a conduit for the hydraulic system to excite the operation of the pneumatic brake.

Gearbox: on the left side of the gearbox is the low-speed shaft, which can increase the speed of the high-speed shaft to 50 times that of the low-speed shaft.

High speed shaft and its mechanical brake: the high speed shaft runs at 1500 rpm and drives the generator. It is equipped with emergency mechanical brake, which is used in case of failure of pneumatic brake or maintenance of wind turbine.

Generator: often referred to as an induction motor or asynchronous generator. On modern wind turbines, the maximum power output is usually 500 to 1500 kilowatts.

Yaw device: turn the engine room with the help of electric motor to make the rotor face the wind. The yaw device is operated by an electronic controller, which can sense the wind direction through the wind vane. The wind turbine yaw is shown in the figure. Usually, when the wind changes its direction, the wind turbine will deflect only a few degrees at a time.

Electronic controller: contains a computer that constantly monitors the state of the wind turbine and controls the yaw device. To prevent any fault (i.e. overheating of gearbox or generator), the controller can automatically stop the rotation of the wind turbi