Chapter 7-Emc Installation; Emc Measures In The Control Panel; Earthing; Screen Earth Kit - Eaton PowerXL DG1 Installation Manual

Chapter 7—EMC installation
N ote: All following information is strongly recommended
but is not necessary if sufficient system design
and validation has been completed.
The responsibility to meet the local system EMC limit
values and electromagnetic compatibility requirements is
the responsibility of the end user or the system operator.
This operator must also take measures to minimize or
remove emissions in the environment concerned (see
figure on Page 50). He must also use means to increase
the interference immunity of the system devices.
In a drive system (PDS) with frequency inverters, you should
take measures for electromagnetic compatibility (EMC) while
doing your planning, because changes or improvements to
the installation site, which are required in the installation
or while mounting, are normally associated with additional
higher costs.
The technology and system of a frequency inverter cause the
flow of high frequency leakage current during operation. All
grounding measures must therefore be implemented with
low impedance connections over a large surface area.
With leakage currents greater than 3.5 mA, in accordance
with VDE 0160 or EN 61800-5-1, either
the protective conductor must have a cross-section of at
•
least 10 mm 2
the protective conductor must be open-circuit monitored,
•
and the supply must be automatically disconnected
in case of discontinuity of the protective earthing
conductor, or
the second protective conductor must be fitted
•
For an EMC-compliant installation, we recommend the
following measures:
Installation of the frequency inverter in a metallic,
•
electrically conducting enclosure with a good connection
to earth
Shielded motor cables (short cable lengths)
•
Ground all conductive components and housings in a drive
•
system using as short a line as possible with the greatest
possible cross-section (Cu-braid)

EMC Measures in the control panel

For EMC-compatible installation, connect all metallic parts
of the device and the switching cabinet together over broad
surfaces and so that high-frequencies will be conducted.
Mounting plates and cabinet doors should make good
contact and be connected with short HF-braided cables. It
is recommended to avoid using painted surfaces (anodized,
chromized). An overview of all EMC measures is provided in
the figure on Page 50.
Install the frequency inverter as directly as possible (without
spacers) on a metal plate (mounting plate).
Route input and motor cables in the switch cabinet as close
to the ground potential as possible. This is because free
moving cables act as antennas.
When laying HF cables (for example, shielded motor cables) or
suppressed cables (for example, input supply cables, control
circuit and signal cables) in parallel, a minimum clearance of
11.81 in (300 mm) is recommended in order to prevent the
radiation of electromagnetic energy. Separate cable routing is
also recommended when large voltage potential differences
are involved. Any necessary crossed cabling between the
control signal and power cables should be implemented at
right angles (90 degrees).
It is recommended to never lay control or signal cables in the
same duct as power cables. Analog signal cables (measured,
reference and correction values) should be shielded.

Earthing

The ground connection (PE) in the cabinet should be
connected from the input supply to a central earth point
(mounting plate). All protective conductors should be routed
in star formation from this earth point and all conductive
components of the PDS (frequency inverter, motor reactor,
motor filter, main choke) are to be connected.
Avoid ground loops when installing multiple frequency
inverters in one cabinet. Make sure that all metallic devices
that are to be grounded have a broad area connection with
the mounting plate.

Screen earth kit

Cables that are not shielded work like antennas (sending,
receiving). Make sure that any cables that may carry disruptive
signals (for example, motor cables) and sensitive cables
(analog signal and measurement values) are shielded apart
from one another with EMC-compatible connections.
The effectiveness of the cable shield depends on a good
shield connection and a low shield impedance.
It is recommended to use only shields with tinned or
nickel-plated copper braiding. Braided steel shields
are unsuitable.
Control and signal lines (analog, digital) should be grounded
on one end, in the immediate vicinity of the supply voltage
source (PES).
POWERXL SERIES VFD MN040002EN—February 2018 www.eaton.com
Chapter 7—EMC installation
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