Application of ANSLE frequency inverter in air compressor.

1. Technical Requirements
Air compressors are a specific type of machine used to increase the pressure of a gas, allowing for transport and increase of pressure of a gas that can satisfy the needs of production technology or power equipment, and is widely used in ceramics, glass, toys, clothing, machinery, plastics and draw benchs. Traditional piston compressors rely on pressure relays to control startup and shutdown. The compression motor usually uses a direct startup or traditional reduced voltage startup, which create a relatively large electrical and mechanical shock. The air pressure fluctuations in the compressor are also quite large with frequent starting and stopping easily damaging the compressor motor. These, in addition to high noise levels, rapid wear and tear of components, as well as high maintenance demands and costs are deficiencies in the application of this technology.

2. Remodeling Solution

The air compressor variable frequency control system is mainly composed of a frequency converter, a pressure sensor and a control and indication circuit as shown in the diagram below:

A pressure sensor component is first used to test the pressure in the pipe network. Next, the detection display instrument sends the output pressure analogue signal to the frequency converter, which then compares the feedback signal and the given signal, using the internal PID of the frequency converter to carry out automatic output frequency regulation, allowing for automatic adjustment of compressor motor speed and output power. This creates a closed-loop feedback system that maintains constant pressure and automatic control in the pipe network.

3. Solution Advantages

After applying variable frequency control remodeling to piston compressors, the following advantages were seen:

■ Smooth soft starts, avoiding electrical and mechanical shock, thus extending the service life of the both the compressor motor and compressor components;

■ The ANSLE frequency inverter full startup torque characteristic satisfied startup requirements of the air compressor under a heavy load;

■ Automatic stepless speed regulation and automatically maintained constant air pressure;

■ Energy saving operation while at the same time providing excellent automated control;

■ Considerable reduction in air compressor noise levels;

■ Able to be used with a parallel air supply from multiple air compressors;

■ Lowered both the cost and amount of maintenance needed for the air compressor;

■ Many protective functions against short circuits, overcurrent, overvoltage, overload, undervoltage, etc.

It is because of these advantages that CHZIRI’s frequency inverters have been widely used in the variable frequency remodeling of air compressors.