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] The reasons for the high exhaust temperature of screw air compressors : 1. High return air temperature; 2. The motor has a large heating capacity; 3. High compression ratio; 4. High condensation pressure; 5. Improper selection of refrigerant.
[pdf] Uses a dedicated variable frequency drive (VFD) for permanent magnet synchronous motors, enabling stepless speed regulation, constant pressure air supply, and soft start. This eliminates idle power consumption and enables intelligent air supply.
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