Shielding - Eaton PowerXL DB1 Installation Manual

3.4.2.2 Motor earthing
3.4.2.3 Earth-fault protection

3.4.3 Shielding

The motor earthing must be connected to one of the earthing terminals on
the variable frequency drive, as well as to the central earth point on the
power drive system (PDS). Earth connections to a neighboring steel element
in the building (e.g., beam, ceiling joist), a ground rod in the ground, or a
mains earth bus must meet the requirements set forth in the applicable
national and regional industrial safety regulations and/or regulations for elec-
trical systems.
A ground leakage current can be produced by variable frequency drives due
to their system characteristics. DB1 series variable frequency drives have
been designed in such a way that the smallest possible leakage current will
be produced in compliance with standards applicable worldwide. In the case
of devices powered with a three-phase supply (DB1-3, etc.), this leakage cur-
rent must be monitored by an AC/DC-sensitive type B residual current
device (RCD).
Cables that are not screened work like antennas (sending, receiving).
￫
For a compliant EMC connection, cables emitting interference
(e.g., motor cables) and susceptible cables (analog signal and
measured values) must be shielded and laid separately from
each other.
The effectiveness of the cable shielding depends on a good shielding con-
nection and a low shielding resistance/impedance.
￫
Use only screens with tinned or nickel-plated copper braiding.
Shields made of steel braids or metal conduits are either not
suitable or suitable only to a limited extent (depending on the
EMC environment).
￫
Control and signal lines (analogue, digital) should always be
grounded on one end, in the immediate vicinity of the supply
voltage source (PES).
DB1 Variable Frequency Drives 09/17 MN040031EN www.eaton.com
3 Installation
3.4 EMC installation
49