Abstract: Three Gorges permanent locks are characterized by their complicated operational conditions and great submergence of the gates and valves, compared with existing locks of home and abroad. If some ripe types and design methods of the hoist equipment are adopted, the scale of the equipment and the difficulty in its manufacture and installation will increase, and the operational safety and reliability will be affected. In tackling key scientific and technical problems on the hoist equipment for Three Gorges permanent locks, extensive computation, analysis and physical made tests are conducted to select the type of the hoist machines, compare the hydrodynamic drag moments of the lock gates and optimize the integration and mechanism of the hoist equipment, the design and operation mode of the hydraulic drive system. Some key technical problems are emphatically solved, creating favorable conditions for safe operation of the locks.

Key words: Direct-coupled hydraulic hoist, Hydrodynamic drag moment, Operation mode, Three Gorges permanent locks