Try to turn the compressor by hand. It should be possible to turn it around. It should turn around smoothly, without any 'hickups' (be sure to completely shut down the air compressor!). Check the isolation of the motor windings.
[pdf] Displacement (m³/min): It refers to the volume of air discharged by the compressor per unit of time, also known as flow rate or volumetric flow rate. Discharge pressure (MPa): It indicates the pressure of the air at the compressor’s outlet, usually measured in megapascals (MPa).
[pdf] If the capacity of the air compressor is really too low, check the following: Check differential pressure over oil separator. Replace separator when necessary. Check and replace compressed air filters (if installed). Compressor does not unload. Check if pressure switch is correctly set and working.
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