ABB PQFM Instruction Manual page 79

Figure 62 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.
PQF-Manager
outputs
Remark:
(a)
bottom
Figure 62: 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
24 Vdc
external
supply
Note: Contacts drawn in non-alarm position
Figure 63: Cabling of the alarm status of a multi-unit filter consisting of masters only, using the
In the Figure 63 above, the external input will be low if:
- Both master units are in alarm OR
(a)
15
NO
(a)
16
Alarm
17
NC
Right hand terminal block when looking from rear, counting from top to
NO Alarm
contact of
master 1
+
NO Alarm
contact of
master 2
-
NO alarm contact on each filter.
Manual Power Quality Filter PQFM ç Electrical design and installation 79
+
24 Vdc
external
supply
-
+
External
digital
input
-
Figure 63 for 2 master filters.
External
digital
input