Magsoft News

Twenty Examples of Magnetism at Work

1. Refrigerator magnets- artwork & messages
2. Refrigerator magnets- to seal and close the doors
3. Metal machine shop holding devices
4. Scrap yard and steel mill lifting
5. Separation of materials
6. Radiation Isotope creation
7. Pure Physics research
8. Motors- automotive, lawn mower, kitchen mixer
9. Incontinence- bladder valve replacement
10. Dentures
11. Levitation of trains
12. Navigation via the compass
13. Store and library item security tags
14. Shark Navigation
15. MRI for moisture & fat content analysis
16. MRI for body and organ images
17. Transmission Line transformers

A study has on the modeling of Non Destructive Testing using eddy currents with FLUX 8.10, 3D application has recently been performed at CEDRAT. FLUX has demonstrated its capacity to obtain high-quality results for this kind of application with reasonable computation time. To obtain these results, one needs to pay particular attention to the modeling of the mesh design, formulations, and the description of probe motion during the simulation of such problems.

A technical paper “ Non Destructive Testing with FLUX 3D application has been created that allows the user to easily reproduce this computation and understand the key points of NDT modeling in FLUX.

Pioneering the field of computation of electromagnetic fields related to ships, FLUX has become a known and renowned reference in the world. This leadership has a long history: • The partnership developed with the LMN, Laboratoire de Magnétisme du Navire, that has enabled since long time to develop the tools needed for the modelling of this application as well as validation of the results versus measurements. • Xavier Brunotte, the technical manager of CEDRAT has lead its PhD on this application in 1991. The topic was: “Modelling of infinity and account for thin magnetic regions. Application to modelling of ship magnetisation”. • Christophe GUERIN, a major actor on FLUX physical aspects in CEDRAT’s Development Team, has developed the “shell regionsâ€? during its PhD in 1994. The topic was: “Determination of Eddy currents losses in transformer tanks. Modelling of thin regions and account for saturation in magnetic material in harmonic states”.

Introduction
To some extent, the winding of a switched reluctance machine [SR motor] could be treated as an air‑gap winding, where the eddy currents in the conductors could be significant. This is most noticeable on the leading (”motoring”) side of a coil between the unaligned and aligned position, which is quite a complex magnetic circuit. For this reason a transient finite element analysis is desirable to verify the affect of eddy currents.

Figure 1a:Mesh of low voltage.

Figure 1b: standard voltage for SR models.