INFLUENCE OF YOKE LEGS SHAPEON AIRGAP UNCERTAINTY

Jozef Paľa – Ján Bydžovský – Oleksandr Stupakov – Ivan Tomáš – Jana Kadlecová – Vladimír Jančárik

   Influence of yoke legs front shape on reproducibility of measuring conditions with change of the air gap between the sample and the attached yoke is investigated. The influence of the air-gap-change on the flux density inside the yoke and on the sample surface (in the centre between the yoke legs) was analysed using the 2D and the 3D FEM modelling. The results of modelling are compared with experimental results obtained from measurements with a Hall probe and differences between them are discussed. From the results it can be seen, that the cylindrical shape of the yoke legs front helps to stabilize the sample surface field gradient, which improves reliability of determination of the inside-sample field with a single Hall probe.

Keywords: finite element method, air gap, yoke method, magnetic measurement

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