Abstract: The invention relates to the use of laser beams for measuring rotors, in particular wind turbines, for determining an imbalance or defining the absolute setting angle and/or measuring a half-profile of a rotor blade, and a method for determining a torsion of the rotor blade as a deviation between two pitch angles. In contrast to the solution in EP 2582970A1, the invention enables the determining of the absolute pitch angle of a rotor blade during operation, without it being necessary to obtain information relating to the rotor blade or reference points with a Known position relative to the pitch axis, in particular using measuring devices that are mobile and/or positioned on the ground. It is also possible to contactlessly detect imbalances.

Abstract: The invention relates to a method for measuring deflection of a substantially elongated hollow component (B) of a wind energy system from a normal position, extended such that it can be used to determine the deflection of the hollow component (B) of a of a wind energy system from a normal position in a simple and accurate manner, and to reliably monitor the same. To this end, the invention proposes that at least one distance sensor (8.1) for measuring distance in a non-contacting, directed manner is disposed at a first position, taking distance measurements from a target point in the direction of a second position within the hollow component (B), and that a measurement target (9.1) is further disposed in the interior of the hollow component (B) at the second position, said target comprising a target surface extending in a direction (x) transverse to a reference plane (R) perpendicular to the measurement direction (10) of the distance sensor (8.

Abstract: The invention relates to a method for measuring deflection of a substantially elongated hollow component (B) of a wind energy system from a normal position, extended such that it can be used to determine the deflection of the hollow component (B) of a of a wind energy system from a normal position in a simple and accurate manner, and to reliably monitor the same. To this end, the invention proposes that at least one distance sensor (8.1) for measuring distance in a non-contacting, directed manner is disposed at a first position, taking distance measurements from a target point in the direction of a second position within the hollow component (B), and that a measurement target (9.1) is further disposed in the interior of the hollow component (B) at the second position, said target comprising a target surface extending in a direction (x) transverse to a reference plane (R) perpendicular to the measurement direction (10) of the distance sensor (8.