Siemens SINAMICS S120 Function Manual page 521

Note
Exceptions for combined operation of Line Modules
Smart Line Modules may be operated together with Basic Line Modules whose last digit of
the order 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
● 5.0% for parallel connections of SINAMICS S120 Active Line Modules and SINAMICS
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
S120 Smart Line Modules when neither module is equipped with a current compensation
control.
S120 Motor Modules when each module operates with a current compensation control.
Function modules
8.10 Parallel connection of power units
521