METHOD AND APPARATUS FOR MEASURING MAGNETIC LOSSES IN FERROMAGNETIC MATERIALS

摘要

The invention is concerned with a method and apparatus for measuring magnetic losses in ferromagnetic materials. According to the invention, an alternating magnetic field having a predetermined frequency and an amplitude which is modulated at a frequency lower than the predetermined frequency is applied to a ferromagnetic material specimen, to thereby cause in the specimen a modulation in temperature at the frequency of modulation of the magnetic field. The temperature modulation at a surface of the specimen having the applied field is then measured at the frequency of modulation of the magnetic field to obtain a measurement value which is substantially proportional to the magnitude of magnetic losses. The magnitude of magnetic losses in the specimen is determined from the measurement value. The method and apparatus of the invention do not necessitate winding coils around the ferromagnetic material specimen, and also enable one to obtain information about the distribution of magnetic losses in the specimen.