Abstract: In a first aspect, the present invention provides a blade pitch system for a wind turbine, comprising at least one multi winding motor comprising a main independent set of control windings and at least one auxiliary independent set of control windings; and at least a main independent power electronic converter for controlling the main independent set of control windings, and an auxiliary independent power electronic converter for controlling the auxiliary independent set of control windings.

Abstract: Wind turbine comprising a rotor having a hub carrying one or more blades, an air intake and a nacelle, the hub being rotatably mounted on a frame and the frame extending forward into the hub, wherein an air flow passage is provided between an inside portion of the hub and the nacelle via at least one first opening to the hub.

Abstract: Wind turbine comprising a hub carrying a plurality of blades, the hub being rotatably mounted on a frame, the frame extending forward into the hub, wherein the frame comprises a manhole arranged in an upper side of the portion of the frame extending forward into the hub and the frame being dimensioned such that an average-size adult human can move around through it at least up to the manhole.

Abstract: It comprises providing at least two metal shell segments arranged adjacent to each other, forming a column of concrete on at least a joint portion of adjacent shell segments, placing a formwork to form said column of concrete, assembling a support framework before providing shell segments, providing an auxiliary sub-structure internal to the shell segments, and an attaching formwork associated both with the internal support framework and to the shell segments. The assembling of the internal support framework may be carried out by providing at least a first series of auxiliary pillars, joining the auxiliary pillars to each other to form a first auxiliary sub-structure and arranging an attaching formwork attached to said auxiliary pillars.

Abstract: The invention relates to a wind turbine rotor comprising a hub, a plurality of blades, and at least one pitch mechanism for rotating at least one of the blades, each pitch mechanism comprising a partial ring gear, a pitch bearing, a pinion that is arranged to mesh with the partial or complete ring gear and a pitch motor arranged for driving said pinion, wherein the pitch bearing is mounted between the hub and a blade, and the ring gear is mounted on the hub or on the blade. The invention further relates to a method of repairing a partial or complete ring gear in a wind turbine rotor, the ring gear comprising a plurality of segments, the method comprising detaching at least a segment of the ring gear and attaching the ring gear in a modified configuration.

Abstract: The invention relates to a method of reducing oscillations in an offshore wind turbine comprising one or more thrusters, the method comprising determining an oscillation of the offshore wind turbine and operating the one or more thrusters such that the oscillation is reduced. The invention further relates to an offshore wind turbine comprising one or more underwater thrusters, oscillation determination system for determining an oscillation of the wind turbine and a control system for operating the underwater thrusters in response to signals received from the oscillation determination system.