2.4 Service Functions
Service information can be displayed on lines 3 and 4.
Included in the data are total operating hours, power-ups
and trips, and fault logs that store status values present at
the 20 most recent trips. The service information is
accessed by displaying items in parameter group 15-**.
Figure 2.6
Parameter group 15 also displays software versions for
various components, hardware identification numbers, and
other useful information and to determine revision status.
130BP095.10
0.0%
15-43 Software Version
99.52
0.00
1 (1)
15-4*
Unit Identification
Figure 2.7
2.5 Filter Inputs and Outputs
2.5.1 Current Transformers
The active filter monitors internal current harmonics and
receives input from external current transformers. A current
transformer (CT) measures electrical current. The CT has a
primary circuit and a secondary circuit. The secondary
circuit duplicates the primary exactly but with a reduced
current load. The AAF receives signals from the external CT
secondary circuit and actively generates an output wave
pattern to compensate for current irregularities. Internally,
the AAF monitors harmonics of the IGBT output along with
the LCL capacitor banks.
2.5.2 Filter CT Input
The active filter operates by receiving signals from the
current transformers (CTs). The signals are processed and
the filter reacts accordingly to programmed instructions.
Invalid signals cause the filter malfunctions or for the filter
to trip. Input signals are wired to the CT terminal. Incorrect
CT settings or improper wiring are the primary reasons for
the filter not starting or causing the unit to trip or
malfunction. Setting CTs is described in
.
The active filter receives current signal input from three
different measure points.
•
External/line power CT input
•
Internal CT input from IGBT current injection
•
Internal CT input from LCL capacitors (AC
capacitors)
All three inputs are 3-phase. These are processed
individually and the filter reacts according to programmed
instructions.
NOTE!
Incorrect CT settings or improper wiring are the primary
reasons for causing the filter to trip or not starting.
2.5.2.1 External CT Input
For LHD units, CTs are built-in. LHD CTs are located in the
drive section at the input plate and have the following
values: D-frame = 500 A, E-frame = 1000 A, F-frame = 1500
A. Signals are input at terminal MK101 on the AFC board.
CAUTION
Line Power (Primary Side) Current
Use a shorting connector on the secondary side of
customer-supplied external current transformers (CT)
whenever current is present on line power (primary side)
and the AFC card is NOT wired to the external CT
terminals. When performing service on an active filter, use
a shorting connector on the secondary side of external CTs
for extra safety. Failure to short out the secondary side of
current transformers when current is present on the
primary side and the AFC card is NOT connected could
damage the current transformer.
Operator Interface and Acti...
VLT Advanced Active Filter AAF006 D and E Frames Service Manual
MG90Z122 - VLT
®
is a registered Danfoss trademark
2-5
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