I thought Brevini was based in the UK, but anyway they don't manufacture wind turbines.  They make planetary gearboxes for yaw and pitch drives.  These are the drives which turn the blades to the proper angle of attack depending on the wind (pitch), and which rotate (yaw) the entire nacelle to as close to perpendicular to the prevailing wind direction as possible, through the command of the central controller software.

"Life shrinks or expands in proportion to one's courage." - Anaïs Nin