Siemens SINAMICS S120 Function Manual page 332

Function modules
7.11 Parallel connection of power units
Permissible and impermissible winding systems for motors in SINAMICS parallel
connections
The following are admissible:
1. Motors with electrically isolated winding systems (multi-winding system) in which the
2. Motors with a common winding system (single winding system) in which all parallel
The following are inadmissible:
1. Motors with electrically isolated winding systems in which the individual systems are out
of phase with one another.
2. Motors with separate winding systems on the line side which have a common, internal
neutral.
Below are two examples illustrating the possible configuration of parallel connections of
motors with a two-winding system or single winding system.
Parallel connection of two Motor Modules on a motor with a two-winding system
Motors with outputs of between about 1 MW and 4 MW for which parallel connections of
power units are normally employed are generally designed with multiple parallel windings. If
these parallel windings are not interconnected inside the motor, but taken separately to its
terminal box(es), then the motor winding systems are separately accessible. In such cases, it
is often possible to dimension the parallel connection of S120 Motor Modules in such a way
that each motor winding system is effectively supplied by a separate Motor Module in the
parallel connection. The diagram below shows this type of arrangement.
Figure 7-30
332
individual systems are not electrically coupled or out of phase with one another.
windings in the motor are interconnected in the winding overhang or terminal box in such
a way that they have the external appearance of a single winding system.
Example 1: parallel connection
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
Drive functions