Test rig for a back-to-back test of a turbine, including an axle supported in at least one bearing fixed to a carrier, a gear coupled to the axle and a motor coupled to the gear, whereby a gear bearing arrangement comprising two radially extending arms to be coupled to the gear and extending in opposite directions, which arms are pivotally connected to a pair of torque arms extending in a basically parallel direction, with the ends of the torque arms being pivotally coupled to a frame including lateral extensions extending in opposite directions with connection segments, to which segments respective second torque arms arranged in a basically vertical direction in respect to the pair of torque arms are pivotally connected, which second torque arms are pivotally connected to a respective connection element arranged at the carrier.

A one-piece planetary carrier includes first and second side walls connected to one another by a plurality of webs. At least one of the webs has a curved outer surface which is directed substantially outward in a radial direction and belongs to a lateral surface of the web. The web includes a transition to the first side wall and a transition to the second side wall. The curved outer surface is convexly curved about a first axis of curvature at the transition to the first side wall and the transition to the second side wall. The curved outer surface has at least one anticlastic region which lies in an axial central section and an axial edge section of the web, with a combination of the axial central section with the axial edge section substantially defining an axial dimension of the planetary carrier.

A one-piece planetary carrier includes first and second side walls connected to one another by a plurality of webs. At least one of the webs has a curved outer surface which is directed substantially outward in a radial direction and belongs to a lateral surface of the web. The web includes a transition to the first side wall and a transition to the second side wall. The curved outer surface is convexly curved about a first axis of curvature at the transition to the first side wall and the transition to the second side wall. The curved outer surface has at least one anticlastic region which lies in an axial central section and an axial edge section of the web, with a combination of the axial central section with the axial edge section substantially defining an axial dimension of the planetary carrier.

A method (1000-1004) for operating a wind turbine (10, 11) including a drive train (64) including a generator (42) and a rotor shaft (44) mechanically connected with the generator (42) and having an axis (30) of rotation, and a rotor (18) having rotor blades (22-22c). The rotor (18) is mechanically connected with the rotor shaft (44) and rotatable about the axis (30) of rotation. The method (1000-1004) includes determining (1100) that the generator (42) is not operating in a power generating mode, and operating (1200) the rotor (18) to move around a predefined desired angular orientation (α.sub.des) with respect to the axis (30) of rotation in an alternating fashion.

A method (1000-1004) for operating a wind turbine (10, 11) including a drive train (64) including a generator (42) and a rotor shaft (44) mechanically connected with the generator (42) and having an axis (30) of rotation, and a rotor (18) having rotor blades (22-22c). The rotor (18) is mechanically connected with the rotor shaft (44) and rotatable about the axis (30) of rotation. The method (1000-1004) includes determining (1100) that the generator (42) is not operating in a power generating mode, and operating (1200) the rotor (18) to move around a predefined desired angular orientation (α.sub.des) with respect to the axis (30) of rotation in an alternating fashion.

Provided is a wind power generation transmission system. A first sun gear is a hollow gear. The first sun gear includes a first end surface and a second end surface opposite to the first end surface. A second planetary carrier includes a third connection end. An outer circumferential surface of the third connection end is provided with external splines. An inner circumferential surface of the first sun gear is provided with internal splines. The third connection end of the second planetary carrier extends from the second end surface to the first end surface and is disposed in the first sun gear so that the external splines of the third connection end are connected to the internal splines of the first sun gear.

Provided is a wind power generation transmission system. A first sun gear is a hollow gear. The first sun gear includes a first end surface and a second end surface opposite to the first end surface. A second planetary carrier includes a third connection end. An outer circumferential surface of the third connection end is provided with external splines. An inner circumferential surface of the first sun gear is provided with internal splines. The third connection end of the second planetary carrier extends from the second end surface to the first end surface and is disposed in the first sun gear so that the external splines of the third connection end are connected to the internal splines of the first sun gear.

Provided is an arrangement for removing and/or exchanging a hydraulic fluid accumulator installed within a hub of a wind turbine, the arrangement including: a first pair of mounting legs each having at an upper portion connector for connecting to a hub component; a second pair of mounting legs each having at an upper portion connector for connecting to a hub component; a first bar connecting the first pair of mounting legs at a lower portion; a second bar connecting the second pair of mounting legs at a lower portion; an elongate resting structure for carrying an accumulator, the resting structure being at one end slidably supported by the first bar and at another end slidably supported by the second bar and being movable in a parallel manner traverse, in particular perpendicular, to a longitudinal direction the resting structure.

Provided is an arrangement for removing and/or exchanging a hydraulic fluid accumulator installed within a hub of a wind turbine, the arrangement including: a first pair of mounting legs each having at an upper portion connector for connecting to a hub component; a second pair of mounting legs each having at an upper portion connector for connecting to a hub component; a first bar connecting the first pair of mounting legs at a lower portion; a second bar connecting the second pair of mounting legs at a lower portion; an elongate resting structure for carrying an accumulator, the resting structure being at one end slidably supported by the first bar and at another end slidably supported by the second bar and being movable in a parallel manner traverse, in particular perpendicular, to a longitudinal direction the resting structure.

The invention relates to a wind turbine comprising a hub, a nacelle, a tower and a power transmission system for increasing the rotational speed from said hub, said power transmission system comprising at least a first and a second epicyclic gear stage, each of said epicyclic gear stages including a ring gear, a planet carrier and a plurality of planet gears, said plurality of planet gears being mounted in the planet carrier and engaging with the ring gear and with a sun gear; wherein each of said plurality of planet gears of at least said first epicyclic gear stage and said second epicyclic gear stage have identical gear profile design parameters.