Abstract : This paper briefly introduces the current status of the original variable frequency drive system of the main inclined shaft conveyor in Chengzhuang Mine, proposes a new renovation scheme and its implementation, and conducts an in-depth analysis and performance comparison of the new and old variable frequency drive systems, demonstrating the excellent application prospects of frequency converters in conveyors. Keywords : Conveyor; Frequency converter; Drive 1 Overview The belt conveyor in the main inclined shaft of Chengzhuang Mine, Jincheng Anthracite Mining Group Co., Ltd., undertakes the main task of hoisting raw coal for the entire mine. Its drive control system is the GTO-IMD variable frequency speed control system produced by GE in the United States. Both its main structure's rectifier and inverter systems, as well as its central control system, were advanced at the time. However, with the increase in service life and the continuous increase in raw coal production in Chengzhuang Mine, the drawbacks of this system have become increasingly apparent. Firstly, there's the issue of spare parts supply for this system. Since similar products abroad typically have a 10-year update cycle, by around 1998, this model of GTO-IMD system had been replaced by newer frequency converters. The US no longer manufactures spare parts for this model, so we had to source them from other countries through GE. This significantly extended the procurement cycle, forcing us to increase the variety and quantity of spare parts in our inventory, tying up substantial funds. Secondly, its control method uses a hybrid digital-analog control, which can lead to system instability or malfunctions. Furthermore, the cooling system used in this GTO-IMD system has extremely high purity requirements for cooling water, far exceeding those of drinking water. Freezing prevention must also be considered in winter, and leaks can cause the GTO or SCR thyristors to break down. Furthermore, its master-slave control method is as follows: the secondary inverter is the master drive, and its power is balanced with the two primary motors via a flexible connection (belt); both primary inverters are slave drives, and their torques are balanced. Since the two motors are coaxial, varying degrees of torque are generated on the shafts of the two reducers. Long-term operation under these conditions can cause shaft fatigue and even breakage. Based on the above, this GTO-IMD variable frequency speed control system is no longer suitable for production development needs, whether in terms of maintenance, production capacity, or operating costs. Therefore, it needs to be upgraded and renovated. [b][align=center]For details, please click: Chengzhuang Mine Main Inclined Shaft Variable Frequency Speed ​​Control System Renovation[/align][/b]