The windmill converts the kinetic energy of a flowing fluid into rotational energy that can be used to power a mechanical load. The turbine incorporates a plurality of plate structures, a plurality of sail/wing structures, and a drive shaft. The plurality of plate structures attach to the plurality of sail/wing structures such that the passage of the flowing fluid through the plurality of sail/wing structures rotates the combined structure. The combined structure formed by the plurality of plate structures and the plurality of sail/wing structures rotates around an axis of rotation. The drive shaft attaches to the combined structure formed by the plurality of plate structures and the plurality of sail/wing structures such that the rotation of the combined structure rotates the drive shaft.

A tool (600; 600′) for aligning tubular structures of a wind turbine comprises: a support part for attaching the tool (600; 600′) to an end region of a first tubular structure (200) so as to extend axially outward therefrom; and a guide part connected to the support part by a bias part and adapted to engage an interior wall (301a) of a second tubular structure (301), wherein the bias part is arranged to urge the guide part to exert a radial force on said interior wall (301a) when the second tubular structure (301) is moved axially toward the first tubular structure 200), thereby to guide the second tubular structure (301) into axial alignment with the first tubular structure (200).

A unique point absorber type wave energy conversion device is disclosed that includes a Power Take Off (PTO) which uses a torsion spring to return a vertical shaft to its original position after being rotated by a rope or cord that pulls a reel via a guide system. This spring return allows the PTO and housing to stay stationary under the wave energy while a buoy at the surface provides an oscillating linear movement. The oscillating rotary motion caused by the interaction of the buoy and spring is converted into a one directional motion via a one-way clutch and is transmitted to generators using a gearbox that increases rotational speed.

Methods, systems, and devices for dynamic wind turbine rotational speed control are described. The method may include attaching a vane shaft to a support arm of the wind turbine, the vane shaft partially inserted into a cylindrical aperture of an airfoil of the wind turbine, rotating an airfoil around a vertical axis of the wind turbine, and controlling, via a torsion spring of the wind turbine, when a rear stop of the speed control assembly exerts a force on the airfoil to reduce the rotational speed of the wind turbine, where the torsion spring is configured to facilitate the rear stop to exert the force on the airfoil when a rotational speed of the wind turbine around the vertical axis exceeds a set rotational speed, where a portion of the vane shaft is inserted into a helical portion of the torsion spring.

A lightning current transfer unit for a wind turbine, the wind turbine comprising a first part and a second part being rotatable relative to each other, wherein the lightning current transfer unit is arranged to provide electrical contact between the first and second parts, the lightning current transfer unit comprising: a first current transfer portion comprising a first slider and configured to be electrically coupled to a first electrically conducting slideway of the first part of the wind turbine, the first slider being rotatable relative to the first slideway; a second current transfer portion configured to be electrically coupled to an electrically conducting portion of the second part of the wind turbine; a first main spring biasing the first slider towards the first slideway; wherein the first slider comprises: a primary contact biased towards the first slideway by the first main spring; a secondary contact arranged to move relative to the primary contact; and a secondary spring arranged between the first main spring and the secondary contact such that the secondary spring biases the primary contact away from the first slideway and biases the secondary contact towards the first slideway.

An oscillation damper for damping unwanted oscillations in oscillation-sensitive systems, such as tall edifices and towers, especially wind turbines. The oscillation damper has a vertical spring mechanism and the oscillation characteristics, such as the frequency and amplitude, and thus the damping capabilities, can be adjusted across a wide range of values.

Disclosed is a wind turbine blade and a method of for attaching one or more components to a sandwich structure element of a wind turbine blade. The Wind turbine blade comprising a bushing inserted through a hole provided through a sandwich structure element, and a first component attached to a first bushing part and an elastically compressible element being arranged between a first component surface of the first component and a first side of the sandwich structure element.

A pendulum mass damper is directed to damping oscillation of tall buildings, towers or similar flexible structures requiring a low frequency tuned mass damper (TMD) for reducing a e.g. wind or earthquake induced displacement response of the structure. A mass (1) is balanced by a first spring system (2a, 2b, 2c) and supported by a carrying part (4) to maintain a vertical position, the carrying part (4) carrying the mass in the vertical direction extends between the mass and a position (C) below the mass, i.e. the weight of the mass is carried or supported from or at a point or level below the mass, wherein the mass at the position (C) below the mass is fixed and/or connected to a unit (5) constituting a base of a supporting system for the mass which unit is floating i.e. the unit can move either horizontally or both horizontally and vertically.

An elastic body and a linear compressor including the same are provided. The linear compressor comprises a cylinder; a piston reciprocating axially inside the cylinder; a drive unit disposed outside the cylinder; a stator cover coupled to a rear of the drive unit; a spring supporter comprising a body portion coupled to a rear of the piston and a seating portion extending outward from the body portion and disposed at a rear of the stator cover; a back plate disposed at a rear of the seating portion; a plurality of first elastic bodies disposed between the stator cover and the seating portion; and a plurality of second elastic bodies disposed between the seating portion and the back plate, wherein the plurality of first elastic bodies and the plurality of second elastic bodies each form a closed space in which a gas is accommodated.

A rotor blade for a wind turbine having an aerodynamic profile which extends from a blade root up to a blade tip and has a leading edge and a trailing edge. An adjustable aerodynamic flap, which can be adjusted between a retracted and a deployed position by means of a flap drive, is provided on the rotor blade. The flap drive comprises a passive control system which controls a flap position depending on rotation speed. The passive control system of the flap drive is low-maintenance and does not interfere with the safety concept of a wind turbine. In comparison with a reference rotor blade without a flap, the rotor blade has increased lift at low wind speeds.