Siemens SINAMICS S120 Manual page 96

Line Modules
3.2 Basic Line Modules
Figure 3-4 Connection example, Basic Line Module, frame size GD
Same phase sequence in the precharging and main circuits
It is absolutely imperative that the precharging and main circuits have the same phase
sequence. If this is not the case, during the brief overlap period, where both contactors are
simultaneously closed, the precharging resistors will be overloaded and could be
destroyed.
94
CAUTION
Basic Line
Module
Manual, (GH3), 01/2013, 6SL3097-4AE00-0BP3
Chassis power units