Vacon NX Active Front End User Manual page 31

Active Front End (AFE)
LCL FILTER
L1
L2
L3
-C1.1 -C1.2
-C2.1
-C3.1 -C3.2
4.7.2.1 Removing discharging resistors
If the LCL filter is used in a network fitted with an earth fault protection relay, these discharging
resistors should be removed. If the discharging resistors are not removed, the earth fault
monitoring device might indicate a very low leakage resistance. The resistors must be connected
so that the capacitors are discharged when disconnecting from the input power. The wiring diagram
of an alternative discharging circuit can be seen in Figure 18. Figure 17 shows the default wiring of
the LCL filter. The discharging resistors should be 10 kΩ, 500 V and 2 W. Failure to ensure the
discharging of capacitors results in a risk of electric shock! Without the discharge resistors, the
capacitors take a very long time to discharge.
Figure 19 (for FI9 and FI10) and Figure 20 (for FI13) have a blue marking on the lead that has to be
removed from each capacitor if the discharge resistor is not to be used.
Warning! If you do not allow a total discharge of the system before starting the modification, it is
likely that you will get an electric shock in spite of the fact the system is disconnected from the
power supply.
24-hour support +358 (0)201 212 575 • Email: vacon@vacon.com
-L1
U2
V2
W2
-R1 -R4
-C4.1 -C4.2
-R2 -R5
-C2.2 -C5.1 -C5.2
-R3 -R6
-C6.1 -C6.2
Figure 16. Vacon LCL filter wiring diagram
-L2.1
U1
-L2.2
V1
-L2.3
W1
-C1
-C3
-C2
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