Flux controlled magnetic barkhausen noise measurements on grain oriented electrical steels

This paper investigates magnetic Barkhausen noise (MBN) in grain-oriented electrical steel using flux-control and its relationship to power losses obtained from standard Epstein tests. The effects of flux, frequency, grain size and texture in five samples of similar thickness with known core loss values were examined. A comparison with a non-oriented sample indicated that the grain oriented Si-Fe has higher magnetic anisotropy and greater MBN signal variability with position, which is associated with its larger grain size. Angular MBN measurements demonstrated a major easy axis along the rolling direction (RD) that was attributed to its Goss texture. An inverse relation between MBN energy and core loss values was observed. The inverse relation was associated with a greater proportion of Barkhausen events with magnetization changes projected out of the plane of the sample. This generates microscopic eddy currents that do not add vectorily to the bulk eddy currents and thereby reduces excess power losses.