Our VFD Inverter can drive both permanent magnet synchronous air compressor and asynchronous air compressor.

  Pneumatic technology is an engineering technology that uses air compressors as the power source and compressed air as the working medium to transmit energy or signals. It is an important means to achieve various production controls and automatic controls. It is used in automobile manufacturing, production automation, and mechanical equipment. , semiconductor and home appliance manufacturing, and packaging automation have broad application prospects. It is an important energy source and control equipment for various industrial enterprises.

  Air compressors can be divided into low-pressure type (0.2Mpa~1.0Mpa), medium-pressure type (1.0Mpa~10Mpa) and high-pressure type (>10Mpa) according to the pressure.

  The most widely used is the twin-screw low-pressure compressor at present, and its basic principle is: two interlocking helical rotors rotate in opposite directions, and the volume of the free space among them gradually decreases along the axial direction, thereby compressing the air between the two rotors.

  It can continuously output pulsation-free compressed air with a large flow rate. The outlet air temperature is about 60 degrees. It is cooled by the post-cooling system to remove water vapor and deteriorated oil mist before being sent to the gas consumer unit.

1. Overview of the working process of air compressor

  Most of the exhaust pressure regulating devices provided by air compressors when leaving the factory are closed intake pipe pressure regulators. Its working principle is that when the air pressure in the air storage tank (wind bag) exceeds the set pressure, the disc valve on the compressor inlet pipe will automatically close, and the compressor will enter the idling and unloading state, and the displacement and pressure of the air compressor will be reduced. It is not constant during operation, and the air consumption often changes due to changes in working conditions, so the air compressor always repeats the full-load-unload working mode when it is working. The working current at full load is close to the rated current of the motor, and the idling current at unloading is about 30%~50% of the rated current of the motor. This part of the current is not doing useful work, but the idling loss of the machine at the rated speed.

2. Relevant requirements when choosing a beard changer for an air machine

  The air compressor is a constant torque load, and a general-purpose VFD Inverter should be selected.

Reasonably adjust the set value of the air supply pressure to achieve stable voltage and energy-saving operation. Select a constant torque inverter with the same capacity according to the rated power of the supporting motor. The VFD Inverter must have a built-in PID adjustment function and a 4~20Ma or 0~10V analog signal interface; the voltage change rate at the place of use must be within the allowable input voltage range of the VFD Inverter.

  The Variable frequency speed regulation of the air compressor can realize automatic and manual control modes.

  In automatic mode, the pressure transmitter is used to detect the output pressure to control the operating speed of the air compressor. The pressure sensor is installed on the main exhaust pipe and converts the detected pressure signal into an analog voltage or current signal and feeds it back to the VFD Inverter. If the air pressure system is operated as a single unit, the built-in PID function of the VFD Inverter can be directly used to realize automatic pressure adjustment. During design and construction, it is necessary to ensure that the power frequency backup device is retained. Once the VFD Inverter fails, the power frequency system can be used to ensure the continuation of production. For enterprises with large air consumption and many air compressors, PLC programming can be used to achieve precise control of more functions and more equipment linkages.

3. Operational effect after transformation

  After the variable frequency transformation of the compressor, the operation is stable, the control precision is higher, and the working pressure remains constant; the automatic operation of the compressor controlled by the frequency converter makes the start and stop more stable. After the equipment is modified, it can realize closed-loop control of air supply pressure, reduce the number of starts and stops of the compressor, reduce the labor intensity of operators, reduce power consumption and mechanical wear, and extend the service life of the equipment.

4. The significance of air compressor variable frequency transformation

(1) Save energy. Compared with the traditional control compressor, the VFD Inverter-controlled compressor has the most prominent effect of saving energy. We can control the air compressor to work in the most economical operating state according to the air consumption.

(2) Improve pressure control accuracy. The variable frequency control system has precise pressure control ability through PID algorithm under automatic control state. The output gas volume of the variable frequency control compressor changes with the change of the motor speed, which effectively improves the quality of the working condition.

(3) Extend the service life of the compressor. The VFD Inverter can start the compressor from a lower frequency while increasing the torque. Its starting acceleration time can be adjusted to avoid direct startup at power frequency. This reduces the impact on the electrical and mechanical components of the compressor during startup, enhances the reliability of system operation, and extends the service life of the compressor.