1 Introduction
The purpose of this manual is to provide detailed technical
information and instructions to enable a qualified
technician to identify faults and perform repairs on VLT
®
Advanced Active Filters in D- and E-frame sizes. It covers
both the stand alone active filter (AAF) and the filter
portion of the VLT
®
Low Harmonic Drive (LHD).
This manual provides the reader with a general view of the
filter's main assemblies and a description of the internal
processing. With this information, technicians should have
an understanding of AAF operation for troubleshooting
and repair.
This manual provides instructions for the active filter
models and voltage ranges described in
1.1 VLT Active Filter Product Overview
VLT
®
Active Filter AAF006 is a device for harmonics and
reactive current mitigation. The unit is designed for instal-
lation in various applications or combined with a
Adjustable frequency drive as a packaged low harmonic
drive solution. The AAF measures the current signal via
external transducers and counteracts the unwanted
elements of the measured current. The unwanted elements
are programmable via the LCP. The active filter can
compensate all harmonics until 40
th
harmonics at the same
time in an overall compensation mode or until the 25
th
harmonics individual selected down to specified value set
via the LCP. The unit is also capable of correcting reactive
currents to harmonize the current and voltage phases,
creating a displacement power factor close to 1. The AAF
also balances the current loads equally on all three phases.
1.2 For Your Safety
1.2.1 Warnings
CAUTION
Active filters contain dangerous voltages when connected
to line power. The connected current transducers may also
hold dangerous voltages when connected. Only a
competent technician should carry out service.
WARNING
For dynamic test procedures, line power is required and all
devices and power supplies connected to line power are
energized at rated voltage. Use extreme caution when
conducting tests in a powered unit. Contact with powered
components could result in electrical shock and personal
injury.
1.
DO NOT touch electrical parts of the filter or
external current transducers when connected to
line power. After removing power from line
power, wait 20 minutes for D-frame and 40 for E-
frame units before touching any electrical parts.
2.
When any repair or inspection is made, line
power must be disconnected.
3.
The STOP key on the control panel does not
disconnect line power.
4.
When servicing external current transformers
(CTs), remove power completely from the
connection point on both line power and
secondary side of the CTs.
5.
Use a shorting connector on the secondary side
of customer-supplied external current
transformers (CTs) whenever current is present on
the line power (primary side) and the AFC card is
NOT wired to the external CT terminals.
1.3 Electrostatic Discharge (ESD)
CAUTION
When performing service, use proper ESD procedures to
prevent damage to sensitive components.
Many electronic components within the unit are sensitive
to static electricity. Voltages so low that they cannot be
easily detected can reduce the longevity and performance
of the AAF, or completely destroy sensitive electronic
components.
Introduction
VLT Advanced Active Filter AAF006 D and E Frames Service Manual
MG90Z122 - VLT
®
is a registered Danfoss trademark
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