Thin band detector for analyses of rotational magnetization in laminated machine cores

Autor: Georgi Shilyashki, Andreas Windischhofer, Yusuke Kanto, Ulrich Meisl, Helmut Pfützner, Markus Giefing
Rok vydání: 2020
Předmět:
Zdroj: Journal of Magnetism and Magnetic Materials. 503:166575
ISSN: 0304-8853
DOI: 10.1016/j.jmmm.2020.166575
Popis: Soft magnetic SiFe cores of rotating machines or 3-phase transformers tend to exhibit rotational magnetization (RM). RM is of high industrial importance, since causing significant increases of both losses and magnetostriction. However, so far, for the direct detection of RM, not any sensor type was available that could be introduced to the inner of a core in non-destructive ways. This paper describes a promising novel principle that takes advantage from so-called tangential induction sensors, as developed recently. The sensor consists of a nano-crystalline ribbon of e.g. 30 mm × 10 mm × 20 µm size. It is placed on the to-be-inspected region of SiFe lamination, with its long axis in transverse direction. With the up-come of significant RM, the ribbon tends to be strongly magnetized, up to saturation. The sensor principle is based on the finding that the slope of upcoming saturation induction increases with increasing so-called axis ratio a of RM. Aiming for a sensor that can be inserted in a machine core without creating a disturbing inter-laminar air gap, a less than 300 µm thick sensor prototype was manufactured by means of a so-called 2D/3D assembler. On a kapton foil as a substrate, the latter produces a winding of eight silver ink turns round the ribbon that acts as a nucleus of a coil. In instants of upcoming saturation, the spike-like coil signal exhibits an amplitude that is proportional to the axis ratio a of RM, in approximation.
Databáze: OpenAIRE
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