Design of experiments for low voltage electrical machine insulation lifetime modeling

The design of experiments will help to underline the influence of combined operating constraints in insulation reliability of low voltage electrical machines in aerospace applications in the more electric aircraft. Kapton films and coated wires were subjected to an accelerated ageing under combined stresses (V_RMS, frequency, DC voltage, and temperature). It is shown in this paper, that the parameters can be classified with respect to their influence order. Frequency shift from 1 to 10 kHz is more hazardous than a RMS voltage shift from 0.7 to 1.2 kV or a temperature shift from 150 to 200°C. Thanks to experimental design, different mathematical models of sample life time, relying on statistical analysis, have been established. Moreover, some guidelines that help to derive the wire model form from the film model are proposed.