Abstract: A system for a wind turbine rotor blade, the system includes a pitch system that has a pitch bearing and a wind turbine hub, the bearing being attached to the hub and being attachable to a wind turbine rotor blade, and also including a pitch gear coupled to the pitch system. The pitch gear includes a first discrete segment and one or more other discrete segments, each segment having a plurality of teeth for engaging with and actuator such as a pinion. At least the first segment is held in place by releasable fasteners and extends along the pitch gear by a predetermined amount. The predetermined amount that the first segment extends along the pitch gear is determined based on anticipated wear of the pitch gear.

Abstract: A system for a wind turbine includes a pitch system having a blade pitch bearing and a wind turbine hub, the pitch bearing being attached to the wind turbine hub and arranged to be attachable to a wind turbine rotor blade. A pitch gear, having a gear surface for engaging with an actuator, such as a pinion, is releasably coupled to the pitch system so that the pitch gear, under the action of the actuator, causes relative rotation between the hub and the relevant part of the bearing. Releasably coupling the gear surface to the pitch system can allow easy replacement of the gear without requiring the removal of large components such as the bearing.

Abstract: A wind turbine includes at least one wind turbine blade assembly. The blade assembly includes a blade and a pitch bearing arranged between the blade and a hub of the wind turbine, the blade assembly further including two or more hydraulic pitch cylinders for pitching the blade in relation to the hub. The two or more hydraulic pitch cylinders are arranged to expand in the same angular direction around the rotational axis of the pitch bearing. A method for pitching a blade of a wind turbine includes connecting a first end of the hydraulic pitch cylinders directly or indirectly to the hub; connecting a second end of the hydraulic pitch cylinders directly or indirectly to the blade; and expanding or contracting the hydraulic pitch cylinders in the same angular direction in relation to the rotational axis of the pitch bearing.

Abstract: A pilot circuitry is disclosed for controlling the activation of an emergency feathering system of a wind turbine by means of a pilot pressure, wherein the pilot circuitry comprises at least two parallel control circuits for providing a pilot pressure. Additionally, a selector may be provided for selectively preventing a control circuit from providing the pilot pressure to the emergency feathering system in case of malfunction of the control circuit.

Abstract: A wind turbine is described which comprises a tower, a nacelle mounted to the top of the tower, and a rotor mounted to the nacelle. The rotor comprises two or more blades mounted to a central hub. The hub supports two or more annular pitch bearings associated respectively with the two or more blades. Each pitch bearing defines a bearing plane inclined at a first angle with respect to a horizontal plane when the respective blade is oriented in a downwardly direction in alignment with the tower. Each pitch bearing is spanned by a hub plate; and a work platform integral with or mounted to the hub plate lies generally in a plane at a second angle to the horizontal plane when the respective blade is oriented in a downwardly direction in alignment with the tower, which second angle is less than the first angle. The work platform provides a substantially horizontal platform for use by maintenance personnel when installing or servicing components in and around the hub.

Abstract: A wind turbine for producing power to a utility grid includes a rotor having one or more blades, wherein the rotor further includes one or more hydraulic pitch actuators for actively controlling the pitch angle of one or more of the blades. The wind turbine also includes one or more actuator hydraulic pumps adapted for powering the hydraulic pitch actuators, wherein the one or more actuator hydraulic pumps are powered by a normal operation energy source. The wind turbine further includes an emergency hydraulic pump also adapted for powering the hydraulic actuators, the emergency hydraulic pump being powered by an electrical energy storage. A method for powering one or more hydraulic pitch actuators for actively controlling the pitch angle of one or more blades of a wind turbine is also disclosed.

Abstract: A wind turbine includes a rotor having at least one wind turbine blade connected to a rotor hub through at least one blade pitch bearing. The pitch bearing includes at least one outer ring, at least one center ring and at least one inner ring. The pitch bearing has a first rolling element arrangement between the outer ring and the center ring, and a second rolling element arrangement between the center ring and the inner ring, wherein at least one of the first and the second rolling element arrangements includes at least two rows of rolling elements. The at least two rows are at different axial positions in relation to a rotational axis. The play in the first row of roller elements is greater than the play in the second row of roller elements. A pitch bearing for a wind turbine is also disclosed.

Abstract: A wind turbine having a tower and a rotor hub that is supported by the tower. At least one blade extends from the rotor hub, and a nacelle is located proximate the rotor hub. The wind turbine also has a transport conduit that selectively provides communication between an interior of the nacelle and an interior of the rotor hub. The transport conduit may have a collapsed condition in which the transport conduit is located completely within the nacelle, and an extended condition in which the transport conduit partially extends into the interior of the rotor hub. In a specific embodiment, the transport conduit is a telescoping structure. A method for using the transport conduit includes accessing the interior of the nacelle to position an object therein and transporting the object to the interior of the rotor hub using the transport conduit.

Abstract: A bearing for attaching a wind turbine blade to a wind turbine hub, includes a stationary ring, a movable ring which can rotate relative to the stationary ring, a grease lubrication structure, and a canister for collecting grease. The grease lubrication structure forms an outlet for releasing grease from a space between the stationary ring and the movable ring and the canister comprises an inner space with at least one inlet in releasable fluid communication with the outlet. The outlet and the inlet comprise cooperating coupling elements adapted for releasable snap-connection of the outlet to the inlet. Due to the snap-connection, the canister is easily removed and replaced in connection with maintenance of the wind turbine even though the space in the hub is typically very limited.

Abstract: A method of starting up wind turbine (10) comprises heating first and second components, the first component (32) having a first minimum operating temperature and the second component (42) having a second minimum operating temperature. Heat loss is generated after the second component has been heated to the second minimum operating temperature. The heat loss is transferred to the first component to assist heating the first component to the first minimum operating temperature. The first and second components are cooled after reaching the first and second minimum operating temperatures.

Abstract: A wind turbine for producing power to a utility grid includes a rotor having one or more blades, wherein the rotor further includes one or more hydraulic pitch actuators for actively controlling the pitch angle of one or more of the blades. The wind turbine also includes one or more actuator hydraulic pumps adapted for powering the hydraulic pitch actuators, wherein the one or more actuator hydraulic pumps are powered by a normal operation energy source. The wind turbine further includes an emergency hydraulic pump also adapted for powering the hydraulic actuators, the emergency hydraulic pump being powered by an electrical energy storage. A method for powering one or more hydraulic pitch actuators for actively controlling the pitch angle of one or more blades of a wind turbine is also disclosed.

Abstract: A system for a wind turbine includes a pitch system having a blade pitch bearing and a wind turbine hub, the pitch bearing being attached to the wind turbine hub and arranged to be attachable to a wind turbine rotor blade. A pitch gear, having a gear surface for engaging with an actuator, such as a pinion, is releasably coupled to the pitch system so that the pitch gear, under the action of the actuator, causes relative rotation between the hub and the relevant part of the bearing. Releasably coupling the gear surface to the pitch system can allow easy replacement of the gear without requiring the removal of large components such as the bearing.

Abstract: A system for a wind turbine rotor blade, the system includes a pitch system that has a pitch bearing and a wind turbine hub, the bearing being attached to the hub and being attachable to a wind turbine rotor blade, and also including a pitch gear coupled to the pitch system. The pitch gear includes a first discrete segment and one or more other discrete segments, each segment having a plurality of teeth for engaging with and actuator such as a pinion. At least the first segment is held in place by releasable fasteners and extends along the pitch gear by a predetermined amount. The predetermined amount that the first segment extends along the pitch gear is determined based on anticipated wear of the pitch gear.

Abstract: A wind turbine includes at least one wind turbine blade assembly. The blade assembly includes a blade and a pitch bearing arranged between the blade and a hub of the wind turbine, the blade assembly further including two or more hydraulic pitch cylinders for pitching the blade in relation to the hub. The two or more hydraulic pitch cylinders are arranged to expand in the same angular direction around the rotational axis of the pitch bearing. A method for pitching a blade of a wind turbine includes connecting a first end of the hydraulic pitch cylinders directly or indirectly to the hub; connecting a second end of the hydraulic pitch cylinders directly or indirectly to the blade; and expanding or contracting the hydraulic pitch cylinders in the same angular direction in relation to the rotational axis of the pitch bearing.

Abstract: A pilot circuitry is disclosed for controlling the activation of an emergency feathering system of a wind turbine by means of a pilot pressure, wherein the pilot circuitry comprises at least two parallel control circuits for providing a pilot pressure. Additionally, a selector may provided for selectively preventing a control circuit from providing the pilot pressure to the emergency feathering system in case of malfunction of the control circuit.

Abstract: A wind turbine is disclosed having a rotor with at least two blades and a blade pitch system for controlling the pitch angle of the blades. The blade pitch system comprises for each of the blades, a hydraulic blade pitch drive and at least two valves mutually connected in parallel for controlling a flow of liquid to the hydraulic blade pitch drive for that blade. The valves each comprises an arrangement for providing a variable flow of liquid.

Abstract: The invention provides a bearing for attaching a wind turbine blade to a wind turbine hub, the bearing comprising a stationary ring, a movable ring which can rotate relative to the stationary ring, a grease lubrication structure, and a canister for collecting grease. The grease lubrication structure forms an outlet for releasing grease from a space between the stationary ring and the movable ring and the canister comprises an inner space with at least one inlet in releasable fluid communication with the outlet. The outlet and the inlet comprise cooperating coupling elements adapted for releasable snap-connection of the outlet to the inlet. Due to the snap-connection, the canister is easily removed and replaced in connection with maintenance of the wind turbine even though the space in the hub is typically very limited.

Abstract: A wind turbine includes a rotor having a rotational axis and a wind turbine blade connected to a hub through a pitch bearing. The pitch bearing includes an outer ring, a center ring and an inner ring. The pitch bearing further includes a first rolling element arrangement having at least two rows of rolling elements between the center ring and one of the inner and outer rings, and a second rolling element arrangement having at least one row of rolling elements between the center ring and the other of the inner and outer rings. A first row of the at least two rows is arranged at a first distance from the rotational axis, and a second row of the at least two rows is arranged at a second distance from the rotational axis greater than the first distance. A pitch bearing for a wind turbine is also disclosed.

Abstract: A wind turbine includes a rotor having a rotational axis and a wind turbine blade connected to a hub through a pitch bearing. The pitch bearing includes an outer ring, a centre ring and an inner ring. The pitch bearing further includes a first rolling element arrangement having at least two rows of rolling elements between the centre ring and one of the inner and outer rings, and a second rolling element arrangement having at least one row of rolling elements between the centre ring and the other of the inner and outer rings. A first row of the at least two rows is arranged at a first distance from the rotational axis, and a second row of the at least two rows is arranged at a second distance from the rotational axis greater than the first distance. A pitch bearing for a wind turbine is also disclosed.

Abstract: A wind turbine includes a rotor having at least one wind turbine blade connected to a rotor hub through at least one blade pitch bearing. The pitch bearing includes at least one outer ring, at least one centre ring and at least one inner ring. The pitch bearing has a first rolling element arrangement between the outer ring and the centre ring, and a second rolling element arrangement between the centre ring and the inner ring, wherein at least one of the first and the second rolling element arrangements includes at least two rows of rolling elements. The at least two rows are at different axial positions in relation to a rotational axis. The play in the first row of roller elements is greater than the play in the second row of roller elements. A pitch bearing for a wind turbine is also disclosed.