Operating Line Connection Components Via An Isolating Transformer - Siemens SINAMICS S120 Combi Equipment Manual

Line-side power components
3.8 Line connection versions
3.8.3.5

Operating line connection components via an isolating transformer

An isolating transformer converts the line supply type of the plant or system (e.g. IT system)
to a TN system. Additional voltage adaptation to the permissible voltage tolerance range is
possible.
An isolating transformer must be used in the following cases:
● The insulation of the Motor Module and/or the motor is not suitable for the voltages that
occur.
● There is no compatibility with an existing residual-current protective device.
● The installation altitude is higher than 2000 m above sea level.
● A line filter should be used in a line supply system that is not a TN line supply system with
grounded neutral conductor.
An isolating transformer must have the following properties:
● The transformer secondary must be in the star connection (a delta connection is not
permissible!).
● The neutral conductor must be brought out. It must be connected with the PE of the line
filter, line reactor and S120 Combi (infeed).
Notice: If the neutral conductor is not brought out and/or not connected, then all of the
restrictions of an IT line supply apply!
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SINAMICS S120 Combi
Manual, (GH9), 07/2016, 6SL3097-4AV00-0BP5