A method of dismounting or mounting a rotor blade of a wind turbine involves: supporting a rotor blade of a wind turbine with a ground-based lift system at a tip-side position on the rotor blade in relation to a center of gravity of the rotor blade, and supporting the rotor blade with a nacelle-mounted lift system at a hub-side position on the rotor blade in relation to the center of gravity of the rotor blade, so that the rotor blade is supported by the ground-based lift system and the nacelle-mounted lift system in a substantially non-vertical orientation with respect to the ground; and, then separating the rotor blade from or connecting the rotor blade to a rotor hub of the wind turbine.

In the installation of a rotor blade in horizontal orientation to the hub of a horizontal axis offshore wind turbine, use is made of a blade motion synchronization and positioning device, which comprises a wind turbine coupler, a blade coupler, a motion arm between the wind turbine coupler and the blade coupler, and a controllable motion arm actuator assembly. The method includes bringing and maintaining the blade coupler in a motion compensated receiving position, wherein the arm is operated to compensate for sea state and/or wind induced tower top motion. In receiving position, the coupler is coupled to the blade that is suspended from a crane. The actuator assembly is then operated to gradually bring, and then maintain, the coupled blade in a horizontal motion that is synchronized with tower top motion, and to displace the coupled blade root into a pre-mounting position. Then a mounting motion is performed wherein the blade root is moved into a mounting position and the blade root is fastened to mounting structure by fasteners.

A method for lifting a wind turbine rotor blade using a lifting yoke including a main body attached to a rope-like lifting means, wherein the main body is attached to the rotor blade, wherein at least two gyroscopic stabilization units each arranged laterally offset to the lifting means at the main body and/or the rotor blade are used, wherein the gyroscopic stabilization units each include a rotating member with a deflectable rotational axis, wherein the rotating members apply an adjustable stabilizing torque in at least one stabilizing torque direction in dependence of a disturbance movement of the lifting yoke and/or the rotor blade at least temporarily during lifting is provided.

The present disclosure relates to methods for rotating a locked rotor of a wind turbine in case of an imbalance in a rotor plane of the rotor, comprising: rotating the rotor using an inching tool to apply torque on a drive train of the wind turbine to reduce the imbalance in the rotor plane; and removing a locking pin from a locking disc operatively connected to the rotor after reducing the imbalance in the rotor plane. The methods further comprise estimating a direction of a torque load due to the imbalance in the rotor plane using one or more sensors, and impeding the inching tool to apply torque on the drive train of the wind turbine in the estimated direction of the torque load due to the imbalance. The present disclosure further relates to inching tools and to methods for installing rotor blades on a hub of a wind turbine.

Methods and systems for assembling a wind turbine blade for a wind turbine, can involve performing a vertical displacement of a blade holder elevator during assembly or disassembly of a wind turbine. The vertical displacement can be performed by a hard connection or a flexible connection. The hard connection can be based on a gyroscopic stability and can include a holder operable based on an ability of a wind turbine blade to freely rotate from a hub end on two axes while being elevated or lowered.

A device and a method are for assembling a wind turbine. The device has an assembling structure including a space for assembling a tower and a nacelle of a wind turbine, the space being defined by side portions of the assembling structure, and a hoisting device configured for handling the wind turbine tower and for hoisting the nacelle onto a top of the wind turbine tower while being positioned within said space, the hoisting device being movably connected to a hoisting device support structure arranged on top of the assembling structure. The device further includes a support arrangement for supporting a portion of the wind turbine at least when being within said space and a rotor blade manipulator for bringing rotor blades in contact with the nacelle.

A counterweight tool comprising an attachment element, a lever arm, a weight element, a first locking mechanism, and a first crane connection point. The attachment element being arranged to be attachable to a component of a wind turbine. The lever arm is pivotably connected to the attachment element about a pivot point, said lever arm being pivotable between a first position where the lever arm is arranged at a first angle with respect to the attachment element and a second position where the lever arm is arranged at a second angle with respect to the attachment element, the difference between the first and second angles being greater than 25 degrees. The weight element is attached to the lever arm at a distance from the pivot point, the first locking mechanism being arranged to lock the position of the lever arm with respect to the attachment element in the second position. The first crane connection point being arranged such that when a crane lifts the counterweight tool, by the first crane connection point, the lever arm will be arranged at an angle to the vertical of less than 30 degrees and when the attachment element is fixed in position relative to the crane then lifting or lowering by the crane via the first crane connection point will cause the lever arm to pivot about the pivot point from the first position to the second position. In this way a counterweight tool is provided which has a small horizontal dimension during the initial lifting phase, but which can easily be changed into an effective counterweight tool by just using the lifting capabilities of the crane.

Aspects of the present disclosure are directed to methods for mounting a segmented generator of a wind turbine, wherein the segmented generator for the operation of the wind turbine is formed from two or more generator segments, wherein the generator segments each have a stator segment and a rotor segment, wherein the stator segment for fastening the stator segment to a machine carrier flange of a machine carrier has a stator flange and the rotor segment for fastening to a rotor carrier of a main bearing has a rotor flange, wherein the two or more generator segments in the circumferential direction (U) each extend between two connection interfaces (V1, V2) which are formed for connection with connection interfaces (V1, V2) of generator segments arranged adjacent in the circumferential direction (U).

A counterweight tool comprising an attachment element, a lever arm, a weight element, a first locking mechanism, and a first crane connection point. The attachment element being arranged to be attachable to a component of a wind turbine. The lever arm is pivotably connected to the attachment element about a pivot point, said lever arm being pivotable between a first position where the lever arm is arranged at a first angle with respect to the attachment element and a second position where the lever arm is arranged at a second angle with respect to the attachment element, the difference between the first and second angles being greater than 25 degrees. The weight element is attached to the lever arm at a distance from the pivot point, the first locking mechanism being arranged to lock the position of the lever arm with respect to the attachment element in the second position. The first crane connection point being arranged such that when a crane lifts the counterweight tool, by the first crane connection point, the lever arm will be arranged at an angle to the vertical of less than 30 degrees and when the attachment element is fixed in position relative to the crane then lifting or lowering by the crane via the first crane connection point will cause the lever arm to pivot about the pivot point from the first position to the second position. In this way a counterweight tool is provided which has a small horizontal dimension during the initial lifting phase, but which can easily be changed into an effective counterweight tool by just using the lifting capabilities of the crane.

The present disclosure relates to devices for wind turbine blades and methods for reducing vibrations in wind turbines. More particularly, the present disclosure relates to devices for mitigating vortex induced vibrations and stall induced vibrations, wind turbine blades comprising such devices, and methods for reducing wind turbine vibrations when the wind turbine is parked, especially during wind turbine installation and/or maintenance. A method for mitigating vibrations of a parked wind turbine comprises arranging a device in an inactive state with a wind turbine blade; and causing the device to transition to an active state in which the device grips the wind turbine blade more strongly than in the inactive state.