The rotor is a three blade, mounted up wind of the tower, construction. The power control is by active blade adjustment towards vane position. Blade pitch is adjusted using an electric servomotor on each of the blades.
The complete pitch system is designed fail safe and is fully independent for each blade.
Due to this construction a mechanical brake can be avoided. The pitch system is the primary method of controlling the aerodynamic power input to the turbine. At below rated wind speed the blade pitch setting matches optimum aerodynamic efficiency. At above rated wind speed the control system keeps the average aerodynamic power at the rated level by keeping the rotor speed close to nominal. A gusty wind criterion adjusts blade pitch control parameters to the actual turbulence of the wind.
The rigid rotor hub is a cast iron structure mounted on the main bearing. Rotor blades are connected to the hub using a two rows four point pre-stressed ball bearing. It is sufficiently large to provide a comfortable working environment for two service technicians during maintenance of the pitch system pitch bearings and blade root from inside the structure.