Operation With Ungrounded (It) Supplies - Siemens SINAMICS G120 Hardware Installation Manual

4.2

Operation with ungrounded (IT) supplies

Operation with ungrounded (IT) supplies
IT supplies are fully isolated from the protective earth system, usually by an isolating
transformer. It should be noted, however, that a protective earth is still provided.
Power Modules with built-in filters or external filters must not be used with IT supplies.
If the Power Module connected to an IT supply is required to remain operational if an input or
output phase is connected to ground, then an output reactor must be fitted to prevent
overcurrent tripping. The probability of overcurrent tripping without output reactor increases
with the size of the IT supply.
Power Module FSGX from an IT power system
If the Power Module FSGX is operated from a non-grounded supply/IT system, the
connection bracket for the noise suppression capacitor of the Power Module must be
removed.
1: Remove the two retaining screws
2: Remove the connection bracket
Failing to remove the connection bracket for the noise suppression capacitor on a non-
grounded system/IT system can cause significant damage to the built-in unit.
Operation of the Power Modules without a protective earth is not permitted under any
circumstances.
Power Module PM240
Hardware Installation Manual, 07/2009, A5E00807525B AD
WARNING
WARNING
4.2 Operation with ungrounded (IT) supplies
Connecting
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