Abstract: Method for spectral evaluation of oscillation signals which have been obtained on a rotor blade of a wind power installation with an accelerations sensor. In doing so, instead of the otherwise conventional Fourier transform calculation, the spectral power density is computed. In the evaluation, also signal portions are considered which are not detected in the Fourier transform because they do not go back to oscillations which have been excited in the rotor blade.

Abstract: A device for measuring and optionally correcting the angular offset of two shafts which are connected to one another by way of two universal joints and a third shaft calls for the measurement heads of an optoelectronic alignment device to be adjustably arranged on the shafts by means of at least one pivot joint on one of the clamping devices, with an adjustment capacity. A pertinent method contains matching of the orientation of the measurement heads of the optoelectronic alignment device on the shafts in at least two measurement positions by adjusting the pivot joint.

Abstract: A method for measuring and optionally correcting the angular offset of two shafts which are connected to one another by way of two universal joints and a third shaft calls for the measurement heads of an optoelectronic alignment device to be mounted in the shafts in exactly two measurement positions. These measurement positions are offset by 180° to one another and are located in the plane of the three shafts.