Abstract: A yawing system (2) for a wind turbine and a method of operating the yawing system (2) are disclosed. The yawing system (2) comprises at least one yaw drive arranged to cause the yawing system (2) to perform yawing movements, a yaw bearing allowing mutual movement between two parts of the yawing system (2) during yawing movements, and a hydraulically driven preload mechanism (1) being adapted to provide an adjustable pre-load force to the yaw bearing. The preload mechanism (1) is automatically operated as a consequence of operating the yawing system (2). Thereby it can be ensured that the preload force is adjusted in accordance with whether yawing movements are being performed, or the position of the nacelle should be maintained. The preload mechanism (1) may be modular, in the sense that two or more preload mechanisms (1) operate independently of each other, thereby providing redundancy.

Abstract: A yawing system (2) for a wind turbine and a method of operating the yawing system (2) are disclosed. The yawing system (2) comprises at least one yaw drive arranged to cause the yawing system (2) to perform yawing movements, a yaw bearing allowing mutual movement between two parts of the yawing system (2) during yawing movements, and ahydraulically driven preload mechanism (1) being adapted to provide an adjustable pre-load force to the yaw bearing. The preload mechanism (1) is automatically operated as a consequence of operating the yawing system (2). Thereby it can be ensured that the preload force is adjusted in accordance with whether yawing movements are being performed, or the position of the nacelle should be maintained. The preload mechanism (1) may be modular, in the sense that two or more preload mechanisms (1) operate independently of each other, thereby providing redundancy.