
6.2.2 Capacitor Disconnect
The power factor of the harmonic filter AHF 005/010 is decreasing with decreasing load. At no load the power factor is zero and
the capacitors produce leading current of approximately 25% of rated the filter current. In applications where this reactive
current is not acceptable the terminals X3.1, X3.2, X3.3 and X4.1, X4, X4.3 provide access to the capacitor bank, so it can be
disconnected.
Default (on delivery) the wiring will shorten terminal X3.1 with X4.1, X3.2 with X4.2 and X3.3 with X.4.3. In the case that no
capacitor disconnect is required, no changes should be made to these shorted terminals.
If a disconnection of the capacitors is required a three-phase contactor should be placed between terminals X3 and X4. It is
recommended to use AC3 contactors.
24 V DC
24 – 240 V AC
X 1.1 X1.2 X1.3 X2.1 X2.2 X2.3
X3.1 X 3.2 X3.3 X4.1 X4.2 X4.3
AHF 1
X1.1 X1.2 X1.3 X2.1 X2.2 X2.3
X3.1 X3.2 X3.3 X4.1 X4.2 X4.3
AHF 2
To frequency
converter
relay output
01
02
depending on
contactor type
A
B
A
B
To frequency
converter
digital input
12
27
130BB638.1
1
NOTE
It is not allowed to use one common 3 poled contactor with several paralleled Advanced Harmonic Filters.
NOTE
The AHF filters in stand-by and under low load conditions, when the capacitors are not disconnected, boost the input voltage
with up to 5%. That means that the voltage at the drive terminals is up to 5% higher than the voltage at the input of the filter.
This should be considered at the design of the installation. Special care should be taken in 690V applications where the voltage
tolerance of the drive is reduced to + 5%, unless a capacitor disconnect is used.
NOTE
Only switch the contactor at less than 20% output power. Allow minimum 25 sec. for the capacitors to discharge before re-
connecting
How to Install
AHF005/010 Design Guide
MG.80.C4.02 - VLT
®
is a registered Danfoss trademark
33
6
6
Содержание VLT AHF005
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