Compared with conventional screw air compressors, variable frequency screw air compressors use adjustable air volume and smooth start-up. The air supply pressure is more stable than conventional screw air compressors , but sometimes variable frequency screw air compressors like power frequency compressors appear: Frequent loading and unloading situations.

According to the analysis of this phenomenon, it is found that frequent loading and unloading situations usually occur in the following situations:

1.The air supply pressure and the unloading pressure of the inverter screw air compressor are too close to each other.

When the compressor reaches the air supply pressure, if the air consumption suddenly decreases and the frequency converter is too late to control the motor deceleration, the air production will be too large, resulting in unloading.

Solution:

Set the difference between the supply pressure and the unloading pressure to be larger, usually the difference is ≥0.05MPa

2.When the motor is running at a constant frequency, the panel display pressure fluctuates up and down

Solution:

Change a pressure sensor.

3. The user's air  consumption is unstable, and the air  consumption will suddenly increase and decrease greatly.

At this time, the air supply pressure will change, and the inverter controls the motor to change the output air volume to maintain the stable air supply pressure. However, the rotation speed of the motor has a speed. When this speed cannot keep up with the speed of the air  consumption change at the air  end, it will cause the pressure of the machine to fluctuate, and then there may be loading and unloading situations.

Solution:

(1) The user should not suddenly use multiple air -using equipment, and can turn on the air -using equipment one by one.

(2) Adjust the frequency conversion speed of the inverter faster, so that the change speed of the output air  volume can be increased to adapt to the change of the air  consumption.

(3)Use a large-capacity air  storage tank to buffer.

4. The user's air  consumption is too small

Generally, the frequency conversion range of permanent magnet inverter compressors is 30%~100%, and the frequency conversion range of asynchronous inverter compressors is 50%~100%. When the user's air  consumption is less than the compressor's lower limit output air  quantity, after the air  quantity reaches the set air  supply pressure, the inverter will control the motor to reduce the frequency to the lower limit frequency and the output air  quantity to output compressed air . But because the air consumption is too small, the air supply pressure will continue to rise until the pressure is unloaded and the machine is unloaded. Then the air supply pressure drops, and when the pressure drops below the loading pressure, the machine is reloaded.