Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1803511 | Journal of Magnetism and Magnetic Materials | 2008 | 5 Pages |
Abstract
The behaviour of ferromagnetic materials under very low magnetic field was investigated more than a century ago by Lord Rayleigh. However, it has been shown since that the so-called Rayleigh law fails for very low magnetic fields, although the explanation for this phenomenon was not given. An anomalous B-H behaviour at very low alternating peak flux density in conventional grain-oriented (GO) and non-oriented (NO) electrical steels is reported. It has been found that the initial permeability is constant for all the measured frequencies (from 20 to 400Â Hz) at peak flux density below 0.1Â mT, and in this region the magnetisation is almost reversible (for both GO and NO). At higher flux density the B-H loops become visibly irreversible, with a relatively narrow (for GO) or very wide (for NO) transition region. For GO the B-H loop becomes visibly “distorted” for all frequencies at around 2Â mT. The eddy current loss calculated from the so-called “classical” equation gives values higher than the measured total losses at lower frequencies. Both these measured results are difficult to explain.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Stan Zurek, Faris Al-Naemi, Anthony J. Moses, Philip Marketos,