Emc-Correct Electrical Installation - Danfoss VLT 8000 AQUA series Operating Instructions Manual

EMC-correct electrical installation

525-600 V units do not comply with European
EMC and Low Voltage Directives.
The following is a guideline to good engineering
practice, when installing drives. Following these
guidelines is advised, where compliance with EN 50081,
EN 55011 or EN 61800-3 First environment is required.
If the installation is in EN 61800-3 Second environment,
then it is acceptable to deviate from these guidelines. It
is however not recommended. See also CE labelling,
Emission and EMC test results in this manual.
Good engineering practice to ensure EMC-correct
electrical installation:
• Use only braided screened/armoured motor cables
and braided screened/armoured control 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. See also Earthing of braided
screened/armoured control cables.
• Avoid terminating the screen/armour with
twisted ends (pigtails). Such a termination
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.
• It is important to have good electrical contact
between the mounting plate on which the frequency
converter is installed and the metal chassis of
the frequency converter unit.
Exception:
- IP54/NEMA 12 units designed for wall mounting
- VLT 8042-8062 (200-240 V) IP20/NEMA 1
- VLT 8152-8652 (380-480 V) IP20/NEMA 1
- VLT 8152-8652 (525-690 V) IP20/NEMA 1
This however does not apply to IP54/NEMA 12
units as they are designed for wall mounting and
VLT 8152-8600, 380-480 VAC and VLT 8042-8062,
200-240 VAC in IP20/NEMA 1 enclosure.
• Use starwashers and galvanically conductive
installation plates to secure good electrical
62
®
VLT 8000 AQUA
connections for IP00/Chassis and IP20/NEMA
1 installations.
• Avoid using unscreened/unarmoured motor or
control cables inside cabinets housing the drive(s),
whenever this can be avoided.
• An uninterrupted high frequency connection
between the frequency converter and the motor
is required for IP54/NEMA 12 units.
The next illustration shows an example of an
EMC-correct electrical installation of an IP 20/NEMA
1 frequency converter; the frequency converter has
been installed in a cabinet (enclosure) together with
an output contactor and is connected to a PLC
which, in this example, is installed in a separate
cabinet. For IP 54/NEMA 12 units, VLT 8152-8652
(380-480 V) and VLT 8042-8062 (200-240 V) units
in IP20/NEMA 1 enclosures; screened cables are
connected by using EMC conduits to assure proper
EMC performance. (See next illustration.)
Other ways of making the installation may give as
good an EMC performance, provided the above
engineering practice guidelines are followed.
Please note, that when the installation is not made
according to these guidelines as well as when
unscreened cables and control wires are used, some
emission requirements are not complied with, although
the immunity requirements are fulfilled.
MG.83.A2.02 - VLT is a registered Danfoss trademark