Today soft magnetic composites are innovative materials that could be used in electrical machine production, where new technologies of manufacturing motors with two- or three- dimensional magnetic flux density loci are available. The measurement of the SMC magnetic properties is today considered an important challenge, because high magnetization currents are needed at the saturation point. It is well known that when a small air gap appears in a closed magnetic circuit, the normal magnetization curve has an inclined and more flattened shape. This effect is similar to a shear phenomenon. In powdered SMC materials small air gaps are presented and they are due to the isolation of individual magnetic particles. The high magnetic field strength, which is necessary in the material characterization is directly linked to a high apparent power. A commercial soft magnetic composite was prepared as a toroidal sample with a cross sectional area of 250 mm2, internal diameter of 61 mm and external diameter equal to 71 mm. It was characterized, using a laboratory digital wattmeter. The normal magnetization curve was determined in quasistatic conditions at the frequency of 3 Hz and the energy losses were measured as a function of the frequency at the peak magnetic polarization JP of 100 mT, 250 mT and 500 mT. The frequency was variated between 2 Hz and 250 Hz.

Keywords: Soft magnetic composites (SMC), Energy losses, Normal magnetization curve, Frequency Analysis