Automated measurement system to generate a Preisach-type model of ferromagnetic hysteresis

An automated measurement system for identification of ferromagnetic hysteresis based on Preisach's model is described. The data required consist of incremental permeabilities taken along symmetric hysteresis loops. Magnetic field values are determined by preset values of current in an excitation coil. Magnetic induction values are obtained using an analog integrator for the electromotive force (EMF) induced in a test coil. The integrator output is digitized. The acquisition of successive incremental permeability values as well as the data reduction and display of results are fully automatic. Details of hardware and software implementation as well as the calibration procedure and results obtained for soft iron samples of different composition are presented. The system is particularly suited to investigate the so-called statistical stability of Preisach's model by allowing use of different B-H plane scanning modes.