Siemens SINAMICS S120 Function Manual page 561

Note
Deactivate edge modulation
With a chassis parallel connection and motor with winding systems offset by 30 degrees
(p7003 = 2), the converter can fail with activated edge modulation.
In this case, deactivate the edge modulation (p1802 ≤ 4).
Note
Exceptions for combined operation of Line Modules
Smart Line Modules may be operated together with Basic Line Modules whose last digit of
the Article number is a "3" (Chassis) or a "2" (Cabinet) with one or several CUs if precisely
defined preconditions and the information in the Configuration Manual are maintained. You
can find this information in the "SINAMICS - Low Voltage Configuration Manual
(http://www.automation.siemens.com/mcms/infocenter/dokumentencenter/ld/Documentsu20
Catalogs/lv-umrichter/sinamics-engineering-manual-lv-en.pdf)".
A slight reduction of the rated current must be considered for parallel connection of power
units. The reduction of the rated current (derating) of a power unit for parallel connection is:
● 7.5% for parallel connections of SINAMICS S120 Basic Line Modules and SINAMICS
S120 Smart Line Modules when neither module is equipped with a current compensation
control.
● 5.0% for parallel connections of SINAMICS S120 Active Line Modules and SINAMICS
S120 Motor Modules when each module operates with a current compensation control.
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
Function modules
8.10 Parallel connection of power units
561