[Objective] To address the issues of the poor thermal conductivity in traditional organic insulating materials, which restricts heat dissipation and performance of motors under overload conditions, this study replaced traditional slot insulation paper with high-thermal-conductivity silicon carbide (SiC) insulating varnish for performance enhancement of motors. [Methods] Taking a 1.1 kW asynchronous motor as the test case, a three-dimensional temperature field simulation model was firstly established. Subsequently, thermal analyses were performed via simulation for motors employing standard slot insulation paper and the SiC-based insulating varnish, respectively. Finally, an experimental platform was constructed to measure and compare key performance parameters—including temperature rise, current, and efficiency—of both motor configurations under loads ranging from the rated condition to 1.5-fold load. [Results] Experimental and simulation results indicated that motors utilizing SiC-based high-thermal-conductivity insulating varnish exhibited lower steady-state temperature rises and operating currents compared to traditional insulated motors, while also boasting higher efficiency. Notably, under a 1.5-fold load condition, traditional insulated motors reached a temperature of 150 ℃, triggering an overtemperature shutdown, whereas SiC insulated motors remained stable at 135 ℃ with ample safety margin.This solution proves effective in reducing operational temperature rise and enhancing reliability, rendering it particularly suitable for high-overload applications and scenarios where thermal sensitivity is a critical concern. [Conclusion] The application of SiC high-thermal-conductivity insulating material in stator slot insulation can significantly improve heat dissipation, suppress winding temperature rise, and thereby enhance motor efficiency and overload capacity. This solution can effectively reduce temperature rise and improve reliability, making it particularly suitable for high-overload and heat-sensitive motor applications.