Safety; High Voltage Test; Safety Earth Connection; Emc-Correct Installation - Danfoss VLT AQUA Drive FC 202 Design Manual

How to Install
•
Timed Action Programming
•
Smart Logic Controller Set-up
•
Cascade Control Config. Tool
Ordering number:
Order the CD containing MCT 10 Set-up Software using
code number 130B1000.
MCT 10 can also be downloaded from www.danfoss.com/
BusinessAreas/DrivesSolutions/Softwaredownload/.

5.8.3.2 MCT 31

MCT 31
The MCT 31 harmonic calculation PC tool enables easy
estimation of the harmonic distortion in a given
application. Both the harmonic distortion of Danfoss
frequency converters as well as non-Danfoss frequency
converters with additional harmonic reduction devices,
such as Danfoss AHF filters and 12-18-pulse rectifiers, can
be calculated.
Ordering number:
Order the CD containing the MCT 31 PC tool using code
number 130B1031.
MCT 31 can also be downloaded from www.danfoss.com/
BusinessAreas/DrivesSolutions/Softwaredownload/.

5.9 Safety

5.9.1 High Voltage Test

Carry out a high voltage test by short-circuiting terminals
U, V, W, L , L and L . Energize maximum 2.15 kV DC for
1 2 3
380-500V frequency converters and 2.525 kV DC for 525–
690 V frequency converters for one second between this
short-circuit and the chassis.
WARNING
When running high voltage tests of the entire installation,
interrupt the mains and motor connection if the leakage
currents are too high.

5.9.2 Safety Earth Connection

The frequency converter has a high leakage current and
must be earthed appropriately for safety reasons according
to EN 50178.
WARNING
The earth leakage current from the frequency converter
exceeds 3.5 mA. To ensure a good mechanical connection
from the earth cable to the earth connection (terminal 95),
the cable cross-section must be at least 10 mm
earth wires terminated separately.
®
VLT AQUA Drive FC 202 Design Guide

5.10 EMC-correct Installation

5.10.1 Electrical Installation - EMC
The following is a guideline to good engineering practice
when installing frequency converters. Follow these
guidelines in compliance with EN 61800-3 First
environment. If the installation is in EN 61800-3 Second
environment, industrial networks, or in an installation with
its own transformer, deviation from these guidelines is
allowed but not recommended. See also 2.3.3 Danfoss
Frequency Converter and CE Labelling, 2.9.3 EMC Test Results
(Emission) and 5.10.3 Earthing of Screened/Armoured Control
Cables.
Good engineering practice to ensure EMC-correct
electrical installation:
Leave the screen as close to the connectors as possible.
Illustration 5.106 shows an example of an EMC-correct
electrical installation of an IP 20 frequency converter. The
frequency converter is fitted in an installation cabinet with
2 or 2 rated
an output contactor and connected to a PLC, which is
®
MG20Z102 - VLT is a registered Danfoss trademark
Precautions
•
Use only braided screened/armoured motor
cables and braided screened control cables. The
screen provides a minimum coverage of 80%. The
screen material must be metal, not limited to but
typically copper, aluminum, steel, or lead. There
are no special requirements for the mains cable.
•
Installations using rigid metal conduits are not
required to use screened cable, but the motor
cable must be installed in conduit separate from
the control and mains cables. Full connection of
the conduit from the frequency converter to the
motor is required. The EMC performance of
flexible conduits varies a lot and information from
the manufacturer must be obtained.
•
Connect the screen conduit to earth at both ends
for motor cables as well as for control cables. In
some cases, it is not possible to connect the
screen in both ends. If so, connect the screen at
the frequency converter. See also 5.3.3
Connection to Mains and Earthing.
•
Avoid terminating the screen with twisted ends
(pigtails). It increases the high frequency
impedance of the screen, which reduces its
effectiveness at high frequencies. Use low
impedance cable clamps or EMC cable glands
instead.
•
Avoid using unscreened motor or control cables
inside cabinets housing the frequency converter,
whenever possible.
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