Yaw brakes are used for positioning and holding of pivot-mounted nacelles of wind turbines on the tower, where sensors permanently register possible deviations between actual wind direction and actual nacelle position.
Upon exceeding a permissible deviation, the yaw brakes are completely or partially disengaged in order to allow the re-adjustment of the nacelle by means of the yaw drives.
Subsequently, the clamping force of the typically active yaw brakes is generated again by applying the equivalent hydraulic pressure.