Abstract: This paper introduces the modification of a commutator speed-regulating motor using variable frequency speed control technology. It mainly discusses the basic principle of the frequency converter and the effects of the modification on usage and energy saving. Keywords : Variable frequency speed control, commutator motor, energy saving. The feed belt in the mineral processing and crushing production line needs to adjust the feed rate at any time, requiring adjustable speed of the belt motor. Originally, a commutator speed-regulating motor was used. Due to its long service life and motor aging, the commutator and carbon brushes frequently required maintenance and replacement, resulting in discontinuous production and high equipment maintenance costs. To improve production efficiency and save maintenance costs, given the excellent speed regulation performance and significant energy-saving effect of variable frequency speed control technology, this paper introduces variable frequency speed control technology to modify the original commutator speed-regulating motor. I. Energy-saving principle of variable frequency speed control operation The device that realizes variable frequency speed regulation is called a frequency converter. A frequency converter generally consists of a rectifier, filter, drive circuit, protection circuit, and controller (MCU/DSP). First, a single-phase or three-phase AC power supply is rectified and filtered by a capacitor to form a DC voltage with a basically fixed amplitude, which is then applied to the inverter. The on/off control of the inverter's power components generates a rectangular pulse waveform of a specific shape at the inverter output. Here, the voltage amplitude is controlled by changing the width of the rectangular pulse, and the output frequency is controlled by changing the modulation period. Thus, both the output voltage and frequency are controlled simultaneously on the inverter, satisfying the requirements of variable frequency speed control for U/F coordinated control. [b][align=center]For more details, please click: Application of Variable Frequency Speed ​​Control Technology in Belt Conveyors[/align][/b]