Siemens SINAMICS G120C Operating Instructions Manual page 63

IT system
In an IT line system, all of the conductors are insulated with respect to the PE protective
conductor – or connected to the PE protective conductor through an impedance.
There are IT line supplies where the neutral conductor N is either transferred – or not.
Preconditions and restrictions when connecting an inverter to an IT line system
● Inverter with integrated or external line filter:
– Operation on IT line systems is not permissible.
● Inverter without line filter:
– Operation on IT line systems is permissible.
Inverter connected to an IT line supply
Figure 4-15
Behavior of the inverter when a ground fault occurs
In some instances, even for a ground fault, the inverter should still remain functional. In
cases such as these, you must install an output reactor. This prevents an overcurrent trip or
damage to the drive.
SINAMICS G120C converter
Operating Instructions, 07/2015, FW V4.7 SP3, A5E34263257B AC
IT line supply where the neutral conductor N is transferred and with impedance with
respect to the PE protective conductor
Installing
4.8 Connecting the inverter
59