Abstract : Taking the hoist of blast furnace No. 9 in Maanshan Iron and Steel's No. 1 Ironmaking Plant as an example, this paper analyzes the characteristics of the blast furnace charging hoist drive system, introduces the system design method and issues to be noted during application. Keywords : Blast furnace charging hoist, frequency conversion speed regulation 1 Introduction The original volume of blast furnace No. 9 in Maanshan Iron and Steel's No. 1 Ironmaking Plant was 300m³, and its charging hoist drive system adopted AC wound-rotor motor rotor series resistance speed regulation. Due to the limitations of the matching electrical control equipment, the equipment failure rate was high and the maintenance workload was large, which restricted the normal operation of the equipment. This overhaul expanded the capacity to 350m³, and the main charging hoist motor adopted a 200kW frequency conversion motor. The speed was regulated by a frequency converter, and the frequency converter was required to communicate with the PLC. This enabled soft start and stepless speed regulation of the motor, which could prevent the charging car from derailing at the top of the furnace. The system's self-diagnosis and protection functions are complete and reliable, and the system has performed very well in operation. 2 Requirements of the Charging Car for the Hoist Drive System The mechanical transmission system of the charging car is shown in Figure 1. In Figure 1, the movement of the material car on the inclined bridge is divided into six stages: starting, acceleration, stable operation, deceleration, tipping, and braking. The entire process includes two accelerations and two decelerations. The changes in the material car's speed and acceleration are shown in Figure 2. [b][align=center]For more details, please click: Application of Frequency Converters in Blast Furnace Hoists[/align][/b]