The principle of rotary screw air compression is really no different than reciprocating (piston) compression. Both are positive displacement machines that take in a fixed volume of air at atmospheric press.
[pdf] Checkout Current Transformers (CTs) and check resistance across each one while it is disconnected. All resistances should be within 10% of one another. Also do a diode test on the CT inputs on each compressor module. (The diode test is described in RTAA-SVB10B-EN.)
[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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