Electrical Installation; Control Wires; Power Connections; Earthing - Danfoss VLT AFE 302 Operating Instructions Manual

How to Install

4.4 Electrical Installation

4.4.1 Control Wires

Connect the shields to earth in a proper way to ensure
optimum electrical immunity.
Connect the wires as described in the Operating Instructions
for the frequency converter. Remember to connect the
shields in a proper way to ensure optimum electrical
immunity.
Illustration 4.9 Control Cable Installation
®
VLT Active Front End AFE 302 Operating Instructions Liebherr

4.4.2 Power Connections

Cabling and Fusing
NOTE
Cables General
All cabling must comply with national and local regulations
on cable cross-sections and ambient temperature. Copper
(75°C) conductors are recommended.
The power cable connections are situated as shown below.
The size of the cable cross section is determined according
to the frequency converter's current rating and the local
regulation requirement.
For protection of the frequency converter the correctly rated
fuses must be used or the unit must be with built-in fuses.
The recommended fuses can be seen in the tables in the
fuses section. Always ensure that proper fusing is made
according to the local regulation.

4.4.3 Earthing

The following basic issues need to be considered when
installing a frequency converter to obtain electromagnetic
compatibility (EMC):
Connect the frequency converters to the earth with the
lowest possible conductor impedance. The lowest possible
conductor impedance is obtained by keeping the conductor
short and by using the large possible cross section
conductors.
The metal cabinets of the different devices are mounted on
the cabinet rear plate using the lowest possible HF
impedance. This avoids having different HF voltages for the
individual devices and avoids the risk of radio interference
currents running in connection cables that may be used
between the devices. The radio interference will have been
reduced.
Use the fastening bolts of the devices as HF connection to
the rear plate. It is necessary to remove insulating paint or
similar from the fastening points.
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MG.33.X2.02 - VLT is a registered Danfoss trademark
•
Safety earthing: The frequency converter could
have a high leakage current. It must be earthed
appropriately for safety reasons. Apply local safety
regulations.
•
High-frequency earthing: Keep the earth wire
connections as short as possible.
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