Provided is an alignment tool for a cutting arrangement including a cutting apparatus with a cutting edge for treatment of a workpiece, especially a rotor blade of a wind turbine, in which the alignment tool includes at least one fixation means for fixing the alignment tool to the workpiece and at least one guiding structure to guide the cutting edge of the cutting tool.

The invention relates to a single-point mooring wind turbine having a rotor arranged on a tower, characterized by a design counteracting sway of the wind turbine caused by the rotor torque.

A wind turbine nacelle configured for mounting on a wind turbine tower and for supporting a rotor-supporting assembly, the nacelle comprising a main unit, and at least one auxiliary unit. The auxiliary unit accommodates at least one operative component, e.g. a converter, a transformer, an electrolysis cell, or a battery. An operative component having a similar function is accommodated in another auxiliary unit which thereby facilitate shared operation, and easy and fast maintenance or replacement of the operative component.

A nacelle-mounted multiple-appliance lift system has a first lifting appliance and a second lifting appliance mounted in a nacelle of a wind turbine. The first and second lifting appliances are each mounted on main bearing housing securements, gearbox pillow blocks, or both the main bearing housing securements and the gearbox pillow blocks. The first and second lifting appliances share one or both of the main bearing housing securements and the gearbox pillow blocks. The system permits having multiple lifting appliances mounted at the same in the restricted space of the nacelle.

A rotor arresting device, a wind turbine and a method for arresting and/or rotating a rotor. The rotor arresting device comprises a rotor, a rotational assembly, and a static assembly fixed in position, comprising a toothed disk, which can be arranged on the rotational assembly, having a plurality of arresting recesses arranged along a circumference, wherein two adjacent arresting recesses form a tooth, a first arresting module having at least one first arresting element, a second arresting module having at least one second arresting element, wherein the first and the second arresting module can be arranged on the static assembly, wherein the first and the second arresting element are arranged and designed to engage in arresting recesses of the toothed disk, wherein the spacing of the first arresting element from the second arresting element in the circumferential direction of the toothed disk is a non-integral multiple of a tooth tip spacing of the toothed disk.

A method of retrofitting a wind turbine having a tower and a first energy generating unit with a second energy generation unit is disclosed. The wind turbine has been operated for a first period of time at a first tower life rate and has a first tower life expectancy design value. The method includes determining the tower life of the wind turbine tower used during the first period of time; determining the remaining tower life of the wind turbine tower; replacing the first energy generating unit with the second energy generating unit; and operating the retrofitted wind turbine at a second tower life rate less than the first tower life rate so as to extend the life expectancy value of the tower beyond the first tower life expectancy design value.

A rotor blade for a wind turbine, to a rotor for a wind turbine, to a wind turbine, to a method for producing a rotor blade, to a method for connecting a rotor blade to a rotor hub and to a method for repairing a rotor of a wind turbine. The rotor blade has a connection interface, the connection interface having at least one cutout for receiving a tension element for connecting the rotor blade to a further element of a wind turbine, an outer circumferential surface of the cutout being formed of a connection material and having an internal thread.

A method for performing uptower maintenance of a wind turbine in order to replace the main bearing on the turbine shaft is disclosed. Embodiments of this method to perform maintenance may include installing a rotor lock to resist rotation of the main shaft during maintenance, providing a lifting device in order to elevate the main shaft, removing the main bearing from its main bearing housing, and installing a replacement split main bearing. A crane may also be installed uptower to assist in the maintenance.

A mounting tool includes a base component and an attachment means. The base component includes a mounting portion defining an attachment location for receiving and securing a repair tool so as to maintain the repair tool at a desired repair location and a first receiving portion defining a first cavity for receiving a portion of a wind turbine so as to be externally secured to the wind turbine. The attachment means may be adjustably secured to the first receiving portion of the base component and securable to the portion of the wind turbine so as to secure the mounting tool to the wind turbine at the desirable repair location.

The present disclosure relates to methods for rotating a hub of a wind turbine. The method comprises coupling a first string of a first electrical phase of the stator in series with a second string. Further, the method comprises providing current from a power converter to the first and second strings of the stator to rotate the hub. Besides, the second string is configured to be part of a second electrical phase during normal operation of the wind turbine. Wind turbine generators configured to switch between an inching mode and an operation mode are also disclosed.