Abstract : This paper analyzes the operation of a mine shaft hoisting system and introduces the application of PLC-frequency converter control in the retrofit design of the mine shaft hoisting system. Keywords : Mine shaft hoisting system, hoisting, PLC, frequency converter, control system 0 Introduction Mine hoisting equipment belongs to the second category of loads in production, directly affecting the production status and economic benefits of enterprises. Mine shaft hoisting, due to its advantages of rapid shaft construction, simple surface layout, and low initial investment, has become one of the main hoisting methods for medium and small-sized mines. Traditional mine shaft hoisting equipment uses a relay-contactor control system, utilizing a wound-rotor asynchronous motor rotor with series resistance to achieve speed regulation. Due to frequent switching during production and long equipment operating times, oxidation of the main contactor contacts often leads to poor contact and vibration noise. Furthermore, the complex control circuitry makes fault location difficult during maintenance, thus affecting production. This paper will detail the application of PLC-frequency converter control in the retrofit design of mine shaft hoisting systems. 1. Working Process and Drive System of the Mine Hoisting System The drive system of the mine hoisting system consists of a main motor driving a cylindrical drum through a reducer. Two material cars are alternately loaded via steel wire ropes. When a loaded car rises, an empty car descends. The weight of the empty car acts as a counterweight. Thus, both car cars are driven by a single drum during both upward and downward movements. This not only saves drive motor power but also ensures that one loaded car is always moving upwards, preventing idle travel and keeping the motor constantly running. The drive system's characteristics include: ① Frequent starting, braking, stopping, and reversing with stable speed; ② Operation according to a specific speed pattern. [b][align=center]For more details, please click: Application of Frequency Converters in Mine Hoisting System Retrofit Design[/align][/b]