Hybrid Cooling System With Water Plates and Potting for Outer-Rotor Low-Speed High-Torque PMSMs in Mining Belt Conveyors

Outer-rotor low-speed high-torque permanent magnet motors (LHPMDMs) are favored in mining belt conveyors for their simplicity and reliability, but their torque density is ultimately constrained by poor inner stator heat dissipation. To address this issue, this paper proposes a hybrid cooling method that combines axial water plate insertion with integral winding potting. This design effectively shortens the thermal conduction path from the windings to the coolant. The influence of the water plate structure on the motor's electromagnetic performance is evaluated. A parameterized thermal network model is established for rapid optimization of the water plate position, and CFD simulations are used to optimize key parameters such as the number and thickness of the plates. Comparative analysis reveals that the proposed hybrid method reduces the winding temperature rise by 33% compared to conventional water pipe cooling. Finally, several stator modules equipped with both water plate and water pipe cooling systems are fabricated and experimentally tested, which verifies the correctness of the theoretical analysis and the feasibility of the method.