Delta CT2000 Series User Manual page 624

Chapter 19 EMC Standard Installation GuideCT2000 Series
TT system
TT: The neutral point (N) of the low voltage transformer and the equipment frames (PE) are connected to a
separate earthing point. The Neutral (N) of the transformer and electrical equipment are connected.
IT system
IT: The neutral point of the transformer and electrical equipment are not earthed, only the equipment frames PE are
earthed.
In the IT network, the power distribution system Neutral is either not connected to earth or is earthed via a high
impedance. In such a system, an insulated monitoring device is used for impedance monitoring.
A built-in filter should be disconnected by the RFI-jumper and an external filter should not be installed when the AC
motor drive or the AC servo motor drive is connected to an IT system.
19-11