| 摘要 |
A wind turbine comprises a vertical, rotatable shaft and at least one arm, preferably two or more arms, extending radially outwardly from the shaft and rigidly connected thereto at one end. An aerofoil-shaped blade is connected to the other end of each arm and has a normal operating position in which the blade chord line at the point where the blade connects to the arm is generally normal to a longitudinal axis of the respective arm. The leading edge of the blade is disposed at a fixed acute angle relative to the vertical at all rotational speeds of the blade about the axis of the shaft. The arms preferably also have an aerofoil-shape. An overspeed control mechanism is provided to prevent the blade and arm from rotating beyond a predetermined speed limit about the shaft. The control mechanism includes a hinge mount pivotally connecting the blade to its respective arm. The blade is able to move under excessive speed conditions from the normal operating position to a position wherein the blade creates increased drag. A spring arrangement restores the blade to its normal operating position when the speed limit is no longer being exceeded.
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