Lifetime characteristics of magnet wires under pulse voltage [wire insulation multistress effects]

This paper presents the results of the effect of multistress on the lifetime characteristics of fine gauge magnet wires. Magnet wire insulation is typically enamel that insulates coils used in motor stators, converter transformers, and ignition coils. Accelerated life tests, performed on AWG 43 gauge polyesterimide insulated magnet wires, and estersol coated magnet wires, are compared in this paper. A pulse voltage technique was used in this study. Multistress includes high temperature, high frequency, and high voltages. Lifetime analysis provides us with statistical information such as lifetime characteristics, probability of failures, and lifetime percentiles. The Weibull distribution was used to model life characteristics. The failure data of the aging tests is used to obtain parameters of the frequency-electrical-thermal life model. The life model was used to describe the behavior of insulation in the presence of multistress and is also used to estimate the lifetime of magnet wires at any desired stress level. The parameters of the frequency-electrical-thermal life model used in this study are obtained by a least square method.