Abstract: The 1140V coal mining machine frequency converter is a dedicated frequency converter, characterized by its small size and light weight, suitable for various coal mining machines. By setting the operating frequency using the remote control, the required traction speed and direction of the coal mining machine can be obtained. Keywords: Coal mining machine; Frequency converter; Traction 0 Introduction The 1140V coal mining machine traction frequency converter is a dedicated frequency converter, adopting the AC-DC-AC frequency converter principle. It eliminates the need for a step-down transformer, directly inputting 1140V power to control the speed regulation of the coal mining machine's traction motor, making it an on-board frequency converter for coal mining machines. Its small size and light weight make it suitable for various coal mining machines, especially for thin coal seams where it is the preferred choice. By setting the operating frequency using the remote control, the required traction speed and direction of the coal mining machine can be obtained, improving the overall system efficiency of the coal mining machine and reducing its size and weight. 1. Features of the Coal Mining Machine Traction Frequency Converter (1) It can achieve four-quadrant operation and is suitable for coal mining machines working on steep slope coal mining faces. This frequency converter can enable the coal mining machine to have high-speed shunting function. (2) The frequency converter has an RS-485 communication port, which can realize communication with the host computer of the coal mining machine and display the working status and operating parameters. (3) The frequency converter has a stall function and inverse time current protection. (4) The frequency converter has various protection functions such as overcurrent, overvoltage, undervoltage, overtemperature, and short circuit. (5) The vibration resistance of the frequency converter meets the requirements of the coal mining machine's on-board environment. 2. Technical Parameters of Coal Mining Machine Traction Frequency Converter Input Power Supply: Voltage/V (1140 + 15% - 10%) Input Power Supply: Frequency/Hz (50 ± 5%) Compatible Motor: Power/kW (44～220) Constant Torque: Output/Hz (0～50) Constant Power: Output/Hz (50～80) Constant Torque Characteristics: Maximum torque is 118 times the rated torque; above rated speed, it is constant power. Operating Mode: External/Interactive communication operation. Lead-in/Output Wiring Method: Power line and control line on the front panel. Communication: RS-485 Dielectric Properties: The insulation of 1140V electrical equipment should withstand a power frequency test of 4200V for 1 minute without flashover or breakdown. Insulation Resistance: After applying a power frequency test voltage of 4200V for 1 minute, the insulation resistance before and after the test should be 215 MΩ. Operating Environment Conditions: Altitude not exceeding 1000m. m; ambient temperature -5～+40℃; atmospheric pressure 80～110 kPa; relative humidity not higher than 96% at 25℃. 3 Installation of the frequency converter (1) Before installing the frequency converter, check whether the heat dissipation base of the frequency converter is flat and whether each side plate protrudes from the heat dissipation base. (2) Before installing the frequency converter, check whether the fastening screws, control board and terminals inside the frequency converter are loose due to transportation. (3) Apply a thin and even layer of thermal grease to the heat dissipation base of the coal mining machine. (4) Place the frequency converter on the heat dissipation base of the coal mining machine and move it back and forth and left and right to make good contact between the heat dissipation base of the frequency converter and the heat dissipation base of the coal mining machine. (5) Tighten the mounting screws. 4 Conclusion Practice has proven that the frequency converter has good stability, high reliability and low failure rate when used in conjunction with the coal mining machine.