Effect of test parameters and statistical life data analysis of sinusoidal voltage endurance test on round magnet wires and insulating papers

Enameled round wires and insulating papers are two of the main components of insulating systems for low voltage electrical machines and, in recent decades, several efforts have been made to understand the main factors that determine the performance of these materials in order to build more durable and reliable insulating systems. In this context, this work is focused on sinusoidal voltages supply above the partial discharge thresholds and presents an evaluation of the effects of test voltage and temperature, as well as different statistical treatments on the obtained results from accelerated life tests of enameled wires and insulating papers. The experimental results showed that, in the evaluated inference space, the variation in the results is mostly caused by the test voltage, which has a much greater effect than temperature on the durability of both materials. A reduced linear model was built taking into account the voltage and temperature, but the results in the validation tests were not satisfactory. The experimental data were also modeled by fitting a double stress model taking into account Weibull distributions, and for this model, the estimated lifetime values were better than in the linear model, especially for the insulating papers.