Installation
SIMODRIVE base line A Start-Up
2-19
Line supply system
There are three different line supply networks, e.g. TN system, TT
system and IT system. The TN-C system is applied most widely.
The various system structures are defined below (see Fig.2-11):
●
TN-C system: it is symmetrical 4-conductor or 5-conductor three-
phase network with grounded, loadable star point. The protective
and neutral conductors are connected to the star point.
●
IT system: it is symmetrical 3-conductor or 4-conductor three-phase
network with no directly grounded point, the loads are, e.g.,
connected to groundings.
●
TT system: it is symmetrical 3-conductor or 4-conductor three-phase
network with a directly grounded point, the loads are, e.g., connected
to groundings which are not electrically connected to the directly
grounded point of the network.
