3 Installation
3.5 EMC installat ion
DA1 Variable Frequency Drives 11/16 MN04020005Z-EN www.eaton.com 87
3.5.4 VAR screw
DA1 series variable frequency drives are equipped with an overvoltage filter
for the input supply voltage that is designed to protect the devices from
noise pulses in the mains voltage. Pulse spikes are typically caused by
lightning strikes or by switching operations in other high-power devices on
the same supply.
If high potential tests are performed on a system, these overvoltage
protection components may cause the system to fail the test. In order to
make it possible to perform this type of hipot tests, the overvoltage
protection components can be disconnected by removing the VAR screw.
The screw must be screwed back in after the high potential tests are
performed and the test must then be repeated. The system must then fail
the test, indicating that the overvoltage protection components have been
reconnected.
3.5.5 Screen earth kit
Cables that are not screened work like antennas (sending, receiving).
The effectiveness of the cable screen depends on a good screen connection
and a low screen impedance.
NOTICE
The screw labeled VAR ( Figure 52, page 86) must not be
manipulated as long as the variable frequency drive is
connected to the mains.
￫
For a proper EMC connection, cables emitting interference (e.g.
motor cables) and susceptible cables (analog signal and
measurement values) must be screened and laid separately
from each other.
￫
Use only shields with tinned or nickel-plated copper braiding.
Braided steel shields are unsuitable.
￫
Control and signal lines (analog, digital) should always be
grounded on one end, in the immediate vicinity of the supply
voltage source (PES).
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