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

3.11.3.5

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 greater than 2000 m above sea level, and no TN or TT line
system with grounded neutral point is used.
● 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:
● On the secondary side, the transformer must have a star connection.
● The neutral point must be brought out.
Recommended vector group: Dyn5 or Yyn0
The neutral point must be grounded and connected to the PE of the line filter, line reactor or
AIM and Line Module (infeed).
Comment: If the neutral point is not brought out and/or not connected, then all of the
restrictions of an IT line system apply.
Booksize Power Units
Manual, (GH2), 07/2016, 6SL3097-4AC00-0BP8
Line connection and line-side power components
3.11 Line connection variants
147