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60 Electrical installation
The diagram below shows the typical current THD at nominal current in relation to
supply transformer impedance in a 6-pulse connection.
Current THD
50%
45%
40%
35%
30%
25%
20%
4%
Selecting the power cables
Input AC cabling
￭
The input AC cabling has to be identical (length and cross-sectional area) between all
the parallel-connected supply modules. Each module must have its own shielded
3-conductor input AC cable with the minimum length of 5 m (16.4 ft). This ensures
uniform loading of all the three input phases. If 1 phase cabling or shorter cables than
5 m (16.4 ft) are used to connect the supply modules to the grid, it is required to install
a separate 3-phase AC choke between each ACS880-304LC +A019 module and grid to
ensure current balance between the phases. Separate chokes are not available from
ABB.
PE
PE
PE
5%
6
%
Symmetrical shielded cable with three phase conductors and a concentric
PE conductor as shield. The shield must agree with the requirements of
IEC 61800-5-1. Check with local / state / country electrical codes for al-
lowance.
Symmetrical shielded cable with three phase conductors and symmet-
rically constructed PE conductor, and a shield. The PE conductor must
agree with the requirements of IEC 61800-5-1.
Symmetrical shielded cable with three phase conductors and a concentric
PE conductor as shield. A separate PE conductor is required if the shield
does not agree with the requirements of IEC 61800-5-1.
7
%
8
%
Supply transformer reactance
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