Comprag AV-Series, Operating Manual

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Version 1.1
The compressor is provided with a controller (2) to control parameters, which in automatic mode
tracks consumer air consumption.
Main operating mode:
Upon start-up, the frequency inverter accelerates the compressor over 15 seconds to the maximum
permitted frequency. Pressure builds up to the specified target value. When it is reached, the compres -
sor maintains the set pressure by varying the current signal coming from the frequency inverter. If the
consumption of compressed air increases, the frequency coming from the frequency inverter also in-
creases and thus the rotation of the main motor shaft. If the consumption of compressed air decreas-
es, the frequency coming from the frequency inverter also decreases. However, the compressed-air
pressure remains constant. When the off button is pressed, the frequency inverter lowers the frequen-
cy over 15 seconds to the minimum permitted frequency and switches off the compressor.
Unloading:
When air consumption by the consumer is lower than the lowest possible compressor output, the pneu-
matic system pressure reaches the specified maximum. The solenoid valve is not energised, and it opens.
1. Pressure is fed to the throttle (5) of the suction valve (1), and the throttle is closed. Air intake ceases.
2. The discharge valve (7) opens and releases the internal pressure, unloading the system and the
separator tank (4).
3. The system pressure stabilises, no air is consumed and the compressor switches to standby
mode: the motor does not switch off.
The standby mode time before shutdown or turning on of the compressor can be set on the controller
according to consumption requirements.
Loading:
As air consumption increases, the pneumatic system pressure falls to the minimum set threshold,
and the solenoid valve (3) is energised and closes. Pressurised air to the throttle (5) ceases and the
throttle closes. The discharge valve (7) closes. Air enters the air end (6). The compressor switches
to loading mode.