Sintef Tto as

Wirescan as

Sigbjørn Kolberg

Magnus Blihovde Hjelstuen

Ib-Rune Johansen

Sverre Knudsen

Matthieu Lacolle

Andreas Vogl

Truls Fallet

Zeljko Skokic

Øyvind Nistad Stamnes

Jo Gjessing

Tor Arne Reinen

Magnus Hjelstuen

The invention relates to a solution for how to measure the strain in a washer mounted in a bolt assembly comprising a bolt, nut and washer. The invention concerns a strain measuring washer assembly comprising a plate shaped washer body, sound emitting means and sound detecting means, and a method for using such.

Assembly and method for measuring strain in a washer

A field detector () comprises a field-responsive element () which undergoes a dimensional change when exposed to a predetermined field; and an interferometric read-out arrangement arranged to detect the dimensional change of the field-responsive element. A light source () is arranged to provide a measurement beam reflected from the field-responsive element () and a reference beam not reflected from the field-responsive element (), an optical detector () being disposed so as to detect at least part of an interference pattern produced by the measurement beam and the reference beam. The field-responsive element () has a shape comprising a curved surface and is constrained at least one edge () thereof such that the dimensional change causes the curved surface to be displaced in a direction which changes an optical path length of the measurement beam relative to the reference beam, thereby changing the interference pattern detected by said optical detector.

Detection of fields

The invention relates to a method for cable condition monitoring of an electric cable. The method comprises inducing a test current in the electric cable, measuring a resulting current in a measurement point of the electric cable by measuring a magnetic nearfield of the electric cable, measuring a resulting voltage in the measurement point of the electric cable by measuring an electric nearfield of the cable, calculating an impedance of the electric cable based on the resulting current and the resulting voltage by a line resonance analysis system, and analysing the impedance by the line resonance analysis system establishing a condition of the electric cable. A coupler arrangement providing a non-galvanic connection to the cable is also disclosed.

Method for measuring an impedance of an electric cable, a coupler arrangement and uses thereof

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Oslo, Norway

Sigbjørn Kolberg