On the significance of investigations of transformer core models

Many investigations of transformer core models have been reported in literature. However, low value has been set on the significance of the results for full size cores. It is the intention of this paper to collect experiences concerning model core experiments either from literature or from own investigations. The occurrence of stray fields and leakage fluxes during open-circuit operation prove to be the most serious effect influencing the significance of model core measurements. Stray fields are mainly caused by low numbers of lamination and narrow sheet widths respectively, especially in cases of cores including yokes without magnetization coils.