Organic enameled wire aging monitoring based on impedance spectrum analysis

The proposed paper is focused on the definition of an aging diagnostic method by an analysis of the winding behavior at high frequencies, which strongly depends on the turn-to-turn capacitances. Firstly, it is shown that the thermal aging define variations of the turn-to-turn capacitances which determine changes in winding frequency resonances at high frequencies. These frequencies variations will be used as an aging indicator. A PSpice model is used to simulate the real coil behavior and shows the variation of several high frequency resonances which can be used as indicators for AC machine preventive maintenance program.