A Method for Defining the Mean Path Length of the Epstein Frame

This paper presents a method for the determination of the mean path length of the 25 cm Epstein frame. The proposed method employs two Epstein frames of different dimensions. A standard 25 cm and a revised 17.5 cm Epstein frame were built. The corner areas of the two frames were kept identical. By subtracting the absolute power loss (in watts) measured in strips of the same material by means of the two frames and combining it with the difference in size of the two frames, the exact mean path length of the Epstein frame can be accurately obtained for any magnetizing condition including the case of controlled distorted (nonsinusoidal) magnetization. Results indicate that material permeability and anisotropy are the most important factors that affect the mean path length, whereas the peak flux density and magnetizing frequency also play an important role