Temperature Field Analysis and Design of a New Water-Cooling Structure for Permanent Magnet Synchronous Motors Used in Mining Applications

This paper presents a temperature field analysis and a new water-cooling channel design for a 1000 kW, 72-slot/8-pole permanent magnet synchronous motor used in mining applications. To capture temperature rise data related to electromagnetic losses and fluid heat transfer, a multiphysics coupling model was established, and its accuracy was verified through temperature rise experiments on a prototype. To address the issues of poor temperature uniformity and excessive head loss in the original structure, a double-helix return cooling water channel structure was designed, effectively compensating for the heat exchange capacity at the motor ends and reducing fluid resistance. Comparative analysis shows that this structure significantly outperforms traditional cooling water channels in terms of heat dissipation efficiency, temperature uniformity, and pressure loss. Under optimal geometric parameters—10 spiral turns and a flow velocity of 1 m/s—the maximum winding temperature was suppressed to 67.7 °C, with a winding temperature difference of only 2.6 °C, while the pressure drop was maintained at a low level of 9580 Pa. This study provides a theoretical basis and an efficient engineering solution for the design of water-cooling structures in large mining motors.