O P E R A T I N G D E S C R I P T I O N Cool AirCenter
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| Main Switch, Phase lights, Control voltage 220 V and control fuses, Operating or fault indication, Voltage Supply Axicos, Collective fault signal, Ventilation Technical Directions, Requirements for the operation of the ventilation system, Filter monitoring, Demand supply air and exhaust air, night cool control |
General Directions
Main Switch
The main switch is to be switched on before commissioning commences.
Further functions:
1. Switching off of the complete system in the event of danger.
2. Switching off when work is being performed on the electrical installation, or when work is
being carried out inside the control switchboard.
Phase lights L1 - L2 - L3 (with light prefuse)
In order to operate the system, voltage must be present in all 3 phases.
Should the supply to a phase fail, the motor protection overcurrent relays for the drive motors are
actuated and switch the control system to fault.
When the 3 phases are restored, before starting up again, the motor protection equipment must
be switched to the working position by pushing the keys.
Control voltage 220 V and control fuses
For safety reasons the control voltage is produced by the isolating transformer.
The transformer is protected against overloading and short circuiting by fuses.
Should the complete control system fail, the fuses should be checked.
For the control circuit supply air and exhaust air different fuses are used.
In case of a fault the fuses have to be checked.
Operating or fault indication
The operating status of each motor that is switched on is indicated by the control panel. Should
a fault occur in the motor control e.g. through the actuating of an over current relay or a thermal
contact in the motor winding this is shown as a blinking signal and written into the alarm list of the
panel.
Control voltage 24 V
The low voltage that is necessary for the signal lamps and the PLC-terminal strip is produced by a
power supply. The power supply is protected against overloading and short circuiting by fuses.
In the event of fault the prefuse on the primary side and the fuses on the secondary side should be
checked.
Voltage Supply Axicos
The PLC-station has its own power-supply unit with an input voltage of 230V. It is protected by
fuses.
Collective fault signal
The individual fault signals are, as explained, shown on the control switchboard with the help of
the control panel, and in addition collected in the PLC-station and given out as a PLC collective
fault signal.
The collective fault signal is wired onto an electric terminal and is available for further signal
transmission.
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| Main Switch, Phase lights, Control voltage 220 V and control fuses, Operating or fault indication, Voltage Supply Axicos, Collective fault signal, Ventilation Technical Directions, Requirements for the operation of the ventilation system, Filter monitoring, Demand supply air and exhaust air, night cool control |
Ventilation Technical Directions
1. Requirements for the operation of the ventilation system
Before starting operation the following points should be checked:
All the covers, revision ports and access openings on the aeraulic equipment must be
hermetically closed.
The control units as well as the covers of all electrical equipment must be closed.
2. Filter monitoring
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| Main Switch, Phase lights, Control voltage 220 V and control fuses, Operating or fault indication, Voltage Supply Axicos, Collective fault signal, Ventilation Technical Directions, Requirements for the operation of the ventilation system, Filter monitoring, Demand supply air and exhaust air, night cool control |
The air filters in the supply air units are monitored with the help of a differential pressure switch.
As the dirt in the filters increases, the differential pressure rises so causing the diffential
pressure switch to activate a signal in the PLC station. This is then passed further on over the
collective fault signal.
Attention is also drawn to the dirtying of the filter by way of a visual reading instrument. The
filter should be changed by a pressure difference of approx. 200 Pa.
Control and regulation in the PLC programme:
Demand supply air and exhaust air
The system is switched with the control switch to ON / OFF or READY FOR OPERATION.
Control switch with the positions:
2 = AUTOMATIC / remote control
The supply ventilators and the exhaust air ventilators are free to operate.
By time clock operation automatic the system will be switched on and off by way of the
Axicos PLC-Station.
0 = OFF
1 = MANUAL (ON)
The supply air ventilators and exhaust air ventilators are switched ON directly.
Demand the complete system
a) In the simplest case by way of an external (potential free) contact of the printing machine.
Result: When the printing machine is running the ventilation system also functions.
b) In addition to the the printing machine contact, the ventilation system can be switched on in
combination with the external selector switch. This is carried out by way of the position
HAND in continuous operation, or the position A ( A = Automatic), by way of a time
programme contained in the DDC-programme (time dependent ON / OFF).
Operation: night cool control
The method of operation is only effective when the ventilation system from the normal operating
demand is switched to the OFF function.
This auxillary operation is intended for cooling the warm air in summer time by way of ventilation
operating at night. The low temperature outside air is used to remove the remaining room heat
caused by daytime working. This results in the room being cooled down.
The night cooling system switches on under the following conitions:
• Room temperature in excess of room temperature set point + 3°C
• The difference between inside and outside temperature must be more than 3K
• Night switching time is between 22 p.m. and 6 a.m.
The above conditions are programmed in the PLC-station , however they can be altered at any
time.
With this auxillary operation the supply air temperature base, which is dependent upon the room
temperature, is changed over to a low temperature niveau, to enable ventilation (cooling) with the
highest possible percentage of outside air.
Supply air temperature base by normal operating = +19...26°C
Supply air temperature base by night cooling operation = +17…24°C
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