On the role of hysteresis for flux distributions in transformer cores

Abstract
In spite of the systems simplicity, single phase transformer cores show distinct flux inhomogeneities. Earlier it has been predicted numerically that the latter are affected also by effects of hysteresis which has not been considered so far. The aim of the present work was to verify these predictions experimentally and to interpret the involved physical mechanisms. The flux distribution of a model core was locally analysed by means of search coils through the whole core, the corresponding field by means of tangential H-coils. The results indicate distinct local variations of dynamic hysteresis loops, the interpretation of which is complicated through anisotropy. Hysteresis proves to cause specific effects such as asymmetrical waveforms of flux. Further it yields phase shifts corresponding to antiparallel circulation of flux portions throughout the core.