Analyzing the Magnetic Flux Linkage Characteristics of Alternating Current Rotating Machines by Experimental Method

The magnetically nonlinear behavior of electric alternating current rotating machines is characterized by current dependent magnetic flux linkage characteristics. In this work, the impacts of iron core saturation, iron core saliency, permanent magnets, and squirrel cage in the rotor design on the machines’ behavior, and the respective flux linkage characteristics in forms of hysteresis loops is analyzed. The analysis is based on experimental data by utilizing a stator with two phase-windings that produce magnetomotive forces displaced by electrical 90 , enabling the direct evaluation of flux linkages by measurement of the windings’ voltage and current on the machine terminals. Five rotors of different electromagnetic construction and manufactured from equal materials have been tested in combination with the aforementioned stator. Thus, induction machines, synchronous reluctance machines, permanent-magnet synchronous machines, and their hybrid types are incorporated in the analysis. The work provides a deeper insight into the magnetically nonlinear behavior of the aforementioned machines, which is not available in the current literature. Index Terms—AC machines, magnetic cores, permanent magnets, rotating machine measurements, squirrel cage.