• Unloading valve (UV) is opened by the pressure in the oil separator vessel. The pressure from the oil
separator vessel is released into atmosphere through the unloader (UA).
• The pressure in the oil separator vessel stabilises at low value. A reduced amount of air is compressed to
guarantee a minimal pressure, required for lubrication during unloaded operation.
Air output is stopped (0%), the compressor runs unloaded.
Loaded operation
When the net pressure is below the loading pressure, solenoid valve (Y1) is energised.
• Control pressure is fed from the oil separator vessel via solenoid valve (Y1) to loading plunger (LP) and
unloading valve (UV).
• Unloading valve (UV) closes the air blow-off opening. Loading plunger (LP) moves downwards and
causes inlet valve (IV) to open fully.
Air delivery is resumed (100%), the compressor runs loaded.
2.7 Electrical system
General
Also consult sections Electrical diagram and Electrical connections.
Components
Compressor cubicle
Reference Description
T1 Transformer
Instruction book
2920 7104 10 15