ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Grain oriented 3% silicon iron is widely used as magnetic core material in power devices. It is usually assessed on the basis of its magnetic losses when magnetized as single strips or in the Epstein square. When material is built into cores and magnetized, some flux passes normal to the plane of the laminations and increases the losses of transformers and rotating machines. Pairs of strips were placed together and magnetized at 50 and 60 Hz at ac longitudinal flux densities from 1.0 to 1.8 T and the normal flux density, BN transferred between them was calculated from the emfs induced in search coils located between the strips. Static domain structures were observed using a colloidal technique. Values of BN have been correlated with the domain structures, grain size, and boundary effects. BN was found to be dependent on the static wall spacing in adjacent grains and varied between 0.5 and 3.0 mT with a repeatability better than ±5%. Most large grains had low surface magnetic charge at their boundaries and BN was low. The opposite was found where the flux was transferred between small, not so well oriented, grains. This large normal flux transfer between poorly oriented small grains causes small additional losses in laminated cores.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.349987
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