In many mine sites, the frequency c

In many mine sites, the frequency control system has higher requirements: the speed range should be wide, and the speed can still be adjusted smoothly when the torque changes greatly. In the system of electronic belt weigher, the speed control system controls the material flow by adjusting the belt speed. Sometimes the proportion of materials will change greatly due to the process modification, which requires the speed control system to have a wide range of speed control. In addition, the particle size of materials, bin pressure and even mechanical equipment performance will often change, and the output torque of the speed control system is also required to have a large range of adaptability. Because the frequency converter can change the output frequency and voltage at the same time, that is to say, the N0 on the motor running curve is changed, so that the motor running curve moves down in parallel. Therefore, the frequency converter can make the motor with a smaller starting current and obtain a larger starting torque, that is, the frequency converter can start the heavy load. When the particle size of the material is large or the feeding layer of the belt weigher is thick, the load moment is large, and the frequency conversion speed regulating system can also meet the above requirements.