Abstract: The fibre-optical strain gauge comprises a mechanical construction (1) providing a strain-dependent relative movement of oppositely positioned, spaced apart first and second optical fibre ends in a direction substantially perpendicular to the axial direction of the optical fibres (7a, 7b) and uses the varying transmission of light between the two fibres (7a, 7b) as an indication of the strain. The mechanical construction comprises fibre-holding elements (6a, 6b) for securing the two fibres (7a, 7b) to the mechanical construction (1) in an aligned relationship in the unstrained condition.

Abstract: The invention discloses a detection- and recording system for high intensity electric currents such as lighting currents in a lighting conductor in a wind turbine. The system comprises a detector (6) containing a power supply (7), a measuring circuit (8), and a converter means (9) and furthermore a recording means (11) non-galvanically coupled to said converter means (9) and a measuring coil (5) to be inductively coupled to an electric conductor (2) carrying the high intensity electric current. The power supply (7) receives its electrical energy directly from the lighting current via the power coil (4) which makes the system non-sensitive to mains supply drop-outs.

Abstract: The fibre-optical strain gauge comprises a mechanical construction (1) providing a strain-dependent relative movement of oppositely positioned, spaced apart first and second optical fibre ends in a direction substantially perpendicular to the axial direction of the optical fibres (7a, 7b) and uses the varying transmission of light between the two fibres (7a, 7b) as an indication of the strain. The mechanical construction comprises fibre-holding elements (6a, 6b) for securing the two fibres (7a, 7b) to the mechanical construction (1) in an aligned relationship in the unstrained condition.

Abstract: A process, such as for instance the operation of a machine, is automatically supervised by monitoring at least two of the operational parameters which are desired to have a prescribed relationship to each other. A curve is formed which graphically represents the actual monitored relationship of the parameters, and it is compared to a standard curve representing the desired relationship of the parameters. In the event of a deviation between the curves, a signal is produced to indicate such deviation. An apparatus for carrying out the method is also disclosed.