Compatibility of Ester-Based Cooling Lubricants with Solid Materials in Motors

The compatibility between lubricants and internal motor components, including insulating varnishes and other solid materials, is a critical factor influencing motor insulation performance. This study systematically evaluated the chemical, physical, and electrical property changes of a typical ester-based cooling lubricant in contact with common motor solid materials under high-temperature accelerated aging. Mixed samples of the ester-based lubricant and motor materials were aged at 150°C for 168, 336, and 504 hours, followed by comprehensive testing and evaluation of both the lubricant and materials such as mica and polyimide. The results showed that the polyimide film-reinforced mica tape exhibited incompatibility with the lubricant, whereas polyimide materials alone demonstrated good compatibility. It was also found that the compatibility between the oil and solid materials depends on the composition and insulating performance of the impregnating varnish. This study provides a scientific basis for the practical application of ester-based cooling lubricants and offers valuable guidance for the design and material selection of future high-performance motor systems.