The power consumption of China's air compression system accounts for about 20% to 30% of the total power consumption of enterprises. After installing the frequency conversion speed regulating device on the air compressor, not only can the soft start of the motor be realized, the service life of the equipment can be prolonged, and the electric energy is greatly saved, which is an ideal speed regulating device. The superiority of frequency conversion speed regulation: (1) The frequency conversion speed regulation can realize the stepless smooth speed regulation, and the speed regulation range is large, which is impossible for all kinds of speed regulation. (2) The frequency conversion speed regulation itself has a short-circuit protection function, which will not cause short-circuit and large-current interference to the power grid, so that the power grid runs smoothly. (3) Through the application of frequency conversion speed regulation, energy saving can be achieved. (4) The frequency conversion speed regulation has the function of soft start and soft brake, and most of the time is continuous operation at the rated speed. (5) The transition process is short, the anti-interference ability is strong, and the stability is good. I have a 20m3 piston air compressor with a motor power of 132kW, which is mainly used for passenger car maintenance. In production, the wind pressure in the compressed air pipeline network is relatively stable. In the past, the solenoid valve and the electric contact pressure gauge were used to control the pressure between 0.65 MPa and 0.78 MPa. When the air compressor is running, the system wind pressure reaches the upper limit of the set pressure value; when the unloading solenoid valve acts, the air inlet passage is closed, and the air compressor enters the empty running state. At this time, the air compressor is still running at the rated speed, but its main disadvantages are: (1) The resulting electrical loss is extremely large. (2) The wind pressure cannot be stabilized well during frequent periods when the air volume changes frequently. (3) The valve action value is often changed after one setting, sometimes the working pressure of the whole wind pressure system is high, and the unit pressure air volume is increased. In order to overcome the above shortcomings, reduce the energy loss of air compressors, increase the production cost of enterprises, and improve economic efficiency, it is imperative to use air-saving technology to transform air compressors. In view of the above situation, I used Siemens inverter to realize the frequency conversion speed regulation of the motor, that is, to automatically control the speed and start and stop of the drag motor according to the amount of air volume, and keep the pressure constant within the required range. The so-called variable frequency speed regulation is to change the frequency to make the 50Hz power frequency on the power grid become the required frequency, to achieve stepless speed regulation, and to obtain the speed regulation performance and smooth starting characteristics like the DC motor. It does not consume a part of the rated power of the motor on the speed control system like other speed control methods, and the power saving effect is very obvious.