Simulation and experiment of hybrid permanent magnet-friction braking strategy for overwinding protection

The overwinding protection device serves as the final braking measure in the operation of the mine hoisting system, playing a crucial protective role. However, when implemented in ultra-deep mines, traditional over-winding protection devices encounter issues such as frictional wear and decreased braking efficiency. This paper proposes a hybrid over-winding protection strategy that combines Permanent Magnet Eddy Current Brakes (PMECB) and friction braking to address these challenges. First, this paper analyses the braking characteristics of the axial PMECB, drum friction brake and hydraulic disc brake, and designs a collaborative working strategy based on these characteristics. Subsequently, finite element simulations were conducted to investigate the braking performance under various operating conditions. The simulation results show that, compared with traditional friction devices, the hybrid braking strategy reduces the wear issues and shortens the over-winding distance. The advantages of the hybrid braking strategy are more obvious at higher initial speeds. Finally, hybrid braking experiments were conducted to validate the accuracy of the simulation model and confirm the advantages of the hybrid braking strategy in over-winding protection.