Adjusting Anti Surge Control By Optional Adaption Kit - Nederman VAC 20 Manual De Instrucciones

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 rotate 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 set point,
the damper motor stops.
Remove the sealing from the ducting to gradually increase the airflow and observe the
rise of the motor current. When the current increases to over 5% of the motor current
set point, 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 optional adaption kit

NOTE! For VAC controlled by the HV Control Panel, the testing procedure is the same
but the adjustments are made in the PLC in the HV Control Panel. Ses the HV Control
Panel manual for more information.
Note that the I
e
characteristics and the wiring of the transformer to the current sensing relays, make the
graduation of the scale equal to 10–100 A.
Stop the vacuum unit. The ducting is to be completely sealed off with all outlets closed.
Close the dust collector inlet with a hard board if there is no guarantee that the ducting will
be closed.
Check the settings of the current sensing relays according to Figure 18. Make sure the slide
switches on the underside of the relays are set according to the figure. Figure 18 shows
loosening of the relays from the DIN rail using a screw driver. All relay settings except for I
% are to be set to zero. Set I
Switch on the start and control unit main switch but do not start the vacuum unit. The
green LEDs marked U
Diode) marked R on MIN.
Start the vacuum unit. The characteristic pumping sound is to be heard. No yellow LED is
to light up. Slowly increase I
unit opens a little and the yellow LED goes out again. Repeat until the vacuum unit runs
smoothly without pumping. For large units (30 kW or more) this occurs close to the point
where the valve is fully open and the yellow LED will not go out as I
a certain point. For such a unit, set I
figures in 'Table 7-1: Guidelines for Ie min for 3×400 V' can be used as a guideline for
3×400 V.
Table 7-1: Guidelines for I
Motor, kW
22
30
37
45
For other supply voltages, calculate a rough I
•
400/actual voltage × (I
-dial (the upper dial) is graduated 10-100%. The current transformer
as low as possible and I
e min
on both relays light up as well as the yellow LED (Light Emitting
N
until the yellow LED lights up. The valve inside the vacuum
e min
so that the LED is lit continuously, no higher. The
e min
for 3×400 V
e min
hp
30
40
50
60
for 400 V).
e min
as high as possible.
e max
e min
I , A
e min.
25
32
33
33
setting as follows:
e min
VAC 20 EN
e
is increased beyond
25