Controlling The Compressor; Protecting The Compressor; Monitoring Components Subject To Service (Service Warning); Automatic Restart After Voltage Failure - Atlas Copco GA55 User Manual

User manual
The electronic regulator automatically controls the compressor,
i.e.:
- Loading and unloading the compressor
- Stopping the compressor whenever possible
- Restarting the compressor when required
In order to control the compressor and to read and modify
programmable parameters, the regulator has a control panel
provided with:
- LEDs indicating the status of the compressor
- A display indicating the operating conditions, a service need
or a fault
- Keys to control the compressor and to have access to the
data collected by the regulator
- Buttons to manually start and stop the compressor
- An emergency stop button
In general, the regulator has following functions:
-

Controlling the compressor

-

Protecting the compressor

- Monitoring components subject to service
- Automatic restart after voltage failure (made inactive)
The regulator maintains the net pressure between programmable
limits by automatically loading and unloading the compressor
depending on the air consumption.
The regulator takes into account a number of programmable
settings, such as:
- Unloading pressure
- Loading pressure
- Minimum stop time
- Maximum number of motor starts
The regulator stops the compressor whenever possible (when
the expected unloading period exceeds a programmed value) to
reduce the power consumption and restarts it automatically when
the net pressure decreases. In case the expected unloading period
is below a programmed value, the regulator keeps the compressor
running to prevent too-short standstill periods.
When the compressor has stopped automatically and the net
pressure decreases, the regulator will start the compressor before
the net pressure has dropped to the loading pressure to prevent
the net pressure from falling under the programmed minimum
level.
When stopping the compressor manually, the regulator will
unload the compressor for 30 seconds and then stop the
compressor. 1)
2920 1207 05
If the compressor element outlet temperature exceeds the
programmed shut-down level, the compressor will be stopped.
This will be indicated on the control display.
The compressor will also be stopped in case of overload of the
drive motor or fan motor. 2)
If the compressor element outlet temperature exceeds a
programmed value just below the shut-down level, this will also
be indicated to warn the operator before the shut-down level is
reached.
Regulators for GA90C and for later production GA30 up to -75
are provided with a control function for correct rotation direction
of the motor: a message will appear on the display of the regulator
if the rotation direction is wrong. In this case, switch off the
voltage and reverse two incoming lines.
A warning message also appears if the cooling water temperature
or dewpoint temperature exceeds the warning level. See section
7.2.4.
The regulator continuously monitors critical components (oil,
oil filter, oil separator and air filter). Each input is compared to
programmed limits. Exceeding these limits causes a message
on the control display to warn the operator to replace the
indicated component.
The regulator has a built-in function to automatically restart the
compressor if the voltage is restored after voltage failure. For
compressors leaving the factory, this function is made inactive.
If desired, the function can be activated. Consult Atlas Copco.
Footnotes chapter 1
1) If the compressor was running at that moment in automatic
unloading condition for 10 seconds, it will remain running
unloaded for 30 - 10 = 20 seconds before stopping.
2) For GA30 up to GA90C only.
3