ABB PQFS Installation, Operation And Maintenance Instructions page 61

Figure 43: Cabling of the alarm status of a multi-unit filter consisting of masters only, using the
In the Figure 43, the alarm bulb will be activated when both master units are in alarm.
Figure 44 shows a cabling scheme using a 24 Vdc supply in conjunction with the NO
alarm contact. The scheme assumes that an external digital input monitors the alarm
contact of the filter. In this case the voltage applied to the digital input will be low when:
−
The filter is disconnected from the supply OR.
−
The filter trips due to an error OR.
−
The external 24 Vdc power supply fails.
The voltage applied to the external digital input is high when:
−
The filter is connected to the supply and is not in error AND
−
The external 24 Vdc power supply is in working order.
outputs
Remark:
(a)
Figure 44: Alarm cabling example using NO alarm contact and external digital input
When the filter system consists of multiple master-units and an alarm contact is needed
to signal when the complete system is off, then the NO alarm contacts of all the master
units have to be cabled in parallel. An example is given in
NC Alarm
contact of
master 1
230 Vac
external
power
supply
Note: Contacts drawn in non-alarm position
NC alarm contact on each filter.
PQF-Manager
(a)
15
NO
(a)
16
Alarm
17
NC
Right hand terminal block when looking from rear, counting from top to
Manual Power Quality Filter PQFS  Electrical design and installation 61
NC Alarm
contact of
Alarm bulb
master 2
B
+
24 Vdc
external
supply
-
+
-
Figure 45
External
digital
input
for 2 master filters.