3 Installation
3.5 EMC installat ion
70 DC1 Variable Frequency Drive 04/16 MN04020003Z-EN www.eaton.com
3.5.3.1 EMC screw
In the case of units with a frame size of FS4, the DC link filter (Y class
capacitors) is galvanically connected to the earthing (PE) via the two EMC
screws (motor connection side).
Due to their system characteristics, variable frequency drives with an internal
EMC filter will produce a larger fault current to earth than devices without a
filter. For applications in which this larger leakage current may cause
malfunction messages or disconnections (residual current device), the EMC
filter’s internal protective earth can be disconnected (remove the EMC screw
to do this).
Local EMC regulations must be taken into account when doing so.
If necessary, a specific low-leakage-current EMC filter (DX-EMC...-L) must be
connected upstream.
In connections to isolated power sources (IT networks), the EMC and VAR
screw should be removed. The earth fault monitors required for IT networks
must be suitable for operation with power electronic devices (IEC 61557-8).
3.5.3.2 VAR screw
DC1 variable frequency drives with a frame size of FS1 to FS3 and an IP20
degree of protection are equipped with an overvoltage filter for the input
supply voltage. This overvoltage filter is designed to protect the devices from
noise pulses and high voltage magnitudes 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
NOTICE
The screw labeled EMC must not be manipulated as long as the
variable frequency drive is connected to the mains or there is a
DC link voltage.
￫
The EMC screw galvanically connects the EMC filter’s mains-
side capacitors to the earthing (PE). The screw must be
screwed in all the way to the stop (factory setting) in order for
the variable frequency drive to comply with EMC standards.
NOTICE
In the case of units with a frame size of FS4, both EMC screws
must be either installed or removed, i.e., it is not permissible for
one of them to remain installed while the other one is removed.
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