2 Engineering
2.2 Electrical power network
DA1 Variable Frequency Drives
08/18 MN04020005Z-EN
www.eaton.com
47
2.2 Electrical power network
2.2.1 Mains connection and configuration
DA1 variable frequency drives can be connected to and run on all earthed
groundAC supply systems (TN-S, TN-C, TT grounding systems; please refer
to IEC
60364) without any limitations.
Figure 31: AC supply systems with earthed neutral
The connection and operation of variable frequency drives to asymmetrically
grounded TN networks (phase-grounded delta network “Grounded Delta”,
USA) or non-grounded or high-resistance grounded (over 30
Ω
) IT networks is
only conditionally permissible (internal radio interference suppression filters).
The connection to IT networks is permitted only in sizes FS2 and FS3 in IP20
protection with an unscrewed VAR and EMC screw.
DA1-…-A20C variable frequency drives with an FS2 or FS3 frame size can be
connected to corner-grounded systems or IT grounding systems (not
grounded, insulated). The internal radio interference suppression filter must
be disabled in these cases.
TN-S
TN-C
TT
￫
While planning the project, consider a symmetrical distribution
to the three main phase conductors, if multiple variable
frequency drives with single-phase supplies are to be
connected.
The total current of all single phase devices must not cause an
overload of the neutral conductor (N-conductor).
WARNING
With an unscrewed VAR screw, the variable frequency drive is
no longer protected from transistor overvoltage.
￫
Operation on non-earthed networks (IT) requires the use of
suitable insulation monitoring relays (e. g. pulse-code
measurement method).
￫
In networks with an earthed phase conductor, the maximum
phase-earth voltage must not exceed 300 V AC.
L2
N
L1
L3
PE
L2
PEN
L1
L3
L2
N
L1
L3
