Abstract: The invention relates to a method for the controlled and automatic tensioning of bolts pre-installed in a flange joint between a hub and a main shaft in a nacelle of a wind turbine as well as to a bolt tensioning system for such method. The method comprises arranging a fixture inside the nacelle and mounting a bolt tensioning tool to the fixture which is mounted movable in an axial direction and in a working area perpendicularly hereto. First the flange joint is rotated to position a first set of bolts within the working area of the bolt tensioning tool, and then the bolt tensioning tool is controlled alternately to move the tensioning tool into a position for tensioning a bolt and to tension the bolt, until all bolts of the first set of bolts have been tensioned. The rotation of the flange joint may be controlled by operating a rotation tool operably connected to the main shaft, gearbox, and/or generator.

Abstract: The invention relates to a method for the controlled and automatic tensioning of bolts pre-installed in a flange joint between a hub and a main shaft in a nacelle of a wind turbine as well as to a bolt tensioning system for such method. The method comprises arranging a fixture inside the nacelle and mounting a bolt tensioning tool to the fixture which is mounted movable in an axial direction and in a working area perpendicularly hereto. First the flange joint is rotated to position a first set of bolts within the working area of the bolt tensioning tool, and then the bolt tensioning tool is controlled alternately to move the tensioning tool into a position for tensioning a bolt and to tension the bolt, until all bolts of the first set of bolts have been tensioned. The rotation of the flange joint may be controlled by operating a rotation tool operably connected to the main shaft, gearbox, and/or generator.

Abstract: A structure and a method for modifying an existing design of structure are provided, wherein the structure is provided to at least partially enclose an object that has a large radar cross section. The structure comprises a non-metallic portion having a radar-reflective layer applied to an inclined surface of the structure. The inclined surface is arranged with one or more angles of inclination selected so that the radar cross-section for the structure has a value that is lower than that for the object enclosed in one or more frequency ranges. In a preferred variation, an at least partially detached and appropriately shaped radar-reflective structure may be provided as an alternative to or to supplement the modification of an existing enclosure.

Abstract: A wind turbine includes a rotor having a hub from which a number of wind turbine blades extend, and a spinner mounted on the hub, wherein the spinner includes one or more apertures. The wind turbine is characterized in that it includes one or more aperture covers for entirely or partly covering one or more of the apertures in the spinner and in that the wind turbine further includes one or more aperture adjustment mechanisms for adjusting the effective size of one or more of the apertures, by displacement of one or more of the aperture covers. A method for establishing at least one aperture in the spinner on the hub of a wind turbine rotor and use of a wind turbine are also contemplated.

Abstract: The invention relates to a wind turbine comprising a rotating part including a rotor with at least one blade and a wind turbine hub with at least one enclosure structure or similar wall structure, and a stationary part including a nacelle with at least one enclosure structure or similar wall structure. At least one of said parts comprises a conductive film layer of said enclosure structure with connection to a ground potential, where said film layer forms a shield enclosing said part or parts and protects against electromagnetic fields. The invention also relates to a method to manufacture said enclosure structure.

Abstract: A structure and a method for modifying an existing design of structure are provided, wherein the structure is provided to at least partially enclose an object that has a large radar cross section. The structure comprises a non-metallic portion having a radar-reflective layer applied to an inclined surface of the structure. The inclined surface is arranged with one or more angles of inclination selected so that the radar cross-section for the structure has a value that is lower than that for the object enclosed in one or more frequency ranges. In a preferred variation, an at least partially detached and appropriately shaped radar-reflective structure may be provided as an alternative to or to supplement the modification of an existing enclosure.

Abstract: A wind turbine includes a rotor having a hub from which a number of wind turbine blades extend, and a spinner mounted on the hub, wherein the spinner includes one or more apertures. The wind turbine is characterized in that it includes one or more aperture covers for entirely or partly covering one or more of the apertures in the spinner and in that the wind turbine further includes one or more aperture adjustment mechanisms for adjusting the effective size of one or more of the apertures, by displacement of one or more of the aperture covers. A method for establishing at least one aperture in the spinner on the hub of a wind turbine rotor and use of a wind turbine are also contemplated.

Abstract: The invention relates to a wind turbine comprising a rotating part including a rotor with at least one blade and a wind turbine hub with at least one enclosure structure or similar wall structure, and a stationary part including a nacelle with at least one enclosure structure or similar wall structure. At least one of said parts comprises a conductive film layer of said enclosure structure with connection to a ground potential, where said film layer forms a shield enclosing said part or parts and protects against electromagnetic fields. The invention also relates to a method to manufacture said enclosure structure.