Safety; Emc-Correct Installation - Danfoss VLT Series Design Manual

5. How to Install

5.6. Safety

5.6.1. High Voltage Test
Carry out a high voltage test by short-circuiting terminals U, V, W, L
2.15 kV DC for one second between this short-circuit and the chassis.
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5.6.2. Safety Earth Connection
The frequency converter has a high leakage current and must be earthed appropriately for safety
reasons acording to EN 50178.

5.7. EMC-correct Installation

5.7.1. Electrical Installation -
The following is a guideline to good engineering practice when installing frequency converters.
Follow these guidelines to comply with EN 61800-3
61800-3
former, deviation from these guidelines is allowed but not recommended. See also paragraphs
CE Labelling, General Aspects of EMC Emission
Good engineering practice to ensure EMC-correct electrical installation:
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106
NB!
When running high voltage tests of the entire installation, interrupt the mains and
motor connection if the leakage currents are too high.
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 mm2 or 2 rated earth wires termi-
nated separately.
Second environment,
i.e. industrial networks, or in an installation with its own trans-
Use only braided screened/armoured motor cables and braided screened/armoured con-
trol cables. The screen should provide a minimum coverage of 80%. The screen material
must be metal, not limited to but typically copper, aluminium, 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 drive 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/armour/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
Screened/Armoured Control Cables
Avoid terminating the screen/armour 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/unarmoured motor or control cables inside cabinets housing the
drive(s), whenever this can be avoided.
MG.11.B2.02 - VLT
, L and L
1 2
First environment
. If the installation is in EN
EMC Test Results
and .
.
®
is a registered Danfoss trademark
®
VLT HVAC Drive Design Guide
. Energize by max.
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Earthing of Braided