Initial Start-Up; Checking The Direction Of Rotation; Checking The Y/D Time Setting; Initial Start-Up With Pilot Signal Cable - Nederman VAC 20 Manual De Instrucciones

• Nederman start and control units have the terminals
connected, and in some cases jumped connections.
Verify against the connecting diagrams.
• The pilot signal cable from all valves is linked to the
start and control unit on units with automatic start/
stop.
• Anti-surge control: The current transformer is con-
nected to the relay box.
7.2 Initial start-up
7.2.1 Checking the direction of rotation
At initial start-up, check the direction of rotation by
doing the following:
1 Start the unit.
2 Compare the direction of the motor rotation with
the arrow on the motor.
• If the direction of the motor and the arrow are
the same, allow the starting procedure to con-
tinue.
• If the direction of the motor is different from the
direction of the arrow, change the direction of
the motor by doing the following:
1 Stop the unit.
2 Disconnect power.
3 Open the start and control unit
4 Switch two of the incoming phase conduct-
ors.
7.2.2 Checking the Y/D time setting
The Y/D time setting is factory preset and does
not normally need to be adjusted.
Switching to D mode before the motor has reached
full speed can damage the start and control unit. This
is particularly important when an automatic start and
stop is installed. Too long in Y mode results in an un-
necessary delay before the unit delivers full vacuum.
At initial start-up check the Y/D time setting by doing
the following:
• Make sure the motor sound is constant and high
pitched, indicating full motor power, before the mo-
tor switches to D mode.
7.2.3 Initial start-up with pilot signal cable
For units with pilot signal cable also ensure the fol-
lowing at initial start-up:
• The unit only starts directly when one of the follow-
ing occurs:
• A valve is opened at a worksite, causing the mi-
croswitch to close.
• The test start button is pressed on the start and
control unit (if available).
• The unit shuts down when the time set on the timer
relay has elapsed after the valve is closed (up to 30
minutes).
VAC 20
7.2.4 Adjusting anti-surge control by PLC
For adjusting the anti-surge control by the PLC, see
the start- and control units' manual.
Testing the Anti Surge Control
Observe the damper rotation on the valve angle in-
dicator on the front of the damper motor. For inform-
ation on how to monitor the motor current, see the
start- and control units' installation manual.
Stop the vacuum unit. Seal off the ducting completely
on the inlet side or "suction side". Do not do anything
on the outlet. Start the unit.
Now the airflow through the fan is zero, and the PLC
current control loop senses that the motor current is
below the set point threshold and initiates ASC PLC
opening damper sequence. The damper starts to ro-
tate anti-clockwise "Opening the valve," and lets in
bypass air into the fan.
The motor current increases gradually, and when the
current is within ± 5% of the setpoint, the damper
motor stops.
Remove the sealing from the ducting to gradually in-
crease the airflow and observe the rise of the motor
current. When the current increases to over 5% of the
motor current setpoint, the ASC PLC closing damper
sequence initiates, and the damper starts to rotate
clockwise "Closing the valve." This reduces the bypass
air into the fan until the damper is completely closed.
Finally, verify full functionality of the ASC function by
gradually closing and opening the sealing/restriction
of the airflow on the inlet ducting.
7.2.5 Adjusting anti-surge control by op-
tional adaption kit
For VAC controlled by the HV Control Panel,
the testing procedure is the same but the ad-
justments are made in the PLC in the HV Con-
trol Panel. See the HV Control Panel manual for
more information.
See the manual included in the adaption kit.
8 Maintenance
Read Chapter 2 Safety
ance.
It is recommended to install an hour service meter in
the start and control unit.
The intervals in this chapter are based on the
unit being professionally maintained.
WARNING! Risk of electric shock
Work with electric equipment must be carried
out by a qualified electrician.
before carrying out mainten-
EN
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