Study on Thermal Aging Characteristics of Aerospace Motor Polyimide-Enameled Wires Based on Arrhenius Law

The windings of aerospace motors are fabricated using enameled wires; with polyimide (PI) serving as the primary material for their insulating enamel coatings, thermal aging is the predominant factor contributing to insulation failure in enameled wires. The prolonged natural aging process of enameled wires, coupled with the complexity and sluggish variation rates of dielectric parameters used for aging monitoring, presents significant challenges in developing a universal method for assessing insulation performance. To address this challenge, our study determined accelerated aging conditions based on the Arrhenius law, fabricated twisted-pair specimens, and implemented a step-stress aging protocol, in order to monitor the insulation capacitance (IC) and dielectric dissipation factor (tan δ) of the sample. Finally, a two-parameter Weibull distribution plot was established to characterize the relationship between service life and failure probability. Initial-value normalization combined with B-spline interpolation was employed to construct IC–life correlation curves. A novel method for monitoring PI-enameled wire insulation life using IC variation rate was proposed and experimentally validated, providing a methodological framework for lifespan prediction of aerospace motor windings. Finally, a two-parameter Weibull distribution plot was established to characterize the relationship between service life and failure probability. Initial-value normalization combined with B-spline interpolation was employed to construct IC–life correlation curves. The rationality of the method using IC change rate to monitor the insulation lifetime of polyimide-enameled wire was verified, the lifetime assessment of aviation motor stator windings was achieved by monitoring corresponding dielectric parameters, and a reference standard for the maintenance and support of aviation equipment was provided.