Siemens SINAMICS S120 Function Manual page 333

Owing to the electrical isolation of the winding systems, this arrangement offers the following
advantages:
● No decoupling measures need be implemented at the infeed output in order to limit any
● Both types of modulation system, i.e. space vector modulation and pulse-edge
The current reduction from the rated value for the individual Motor Modules in a parallel
connection is 5 %.
Parallel connection of two Active Line Modules and two Motor Modules on one motor with a
single winding system
It is not possible to use motors with separate winding systems for many applications, e.g. it
might not be possible to implement the required number of winding systems due to the pole
number or because the motor is not supplied by Siemens or because a motor with a
common winding system is already available for the application. In such cases, the outputs
of the parallel-connected Motor Modules are interconnected via the motor cables in the
motor terminal box.
Active Interface Modules isolate switching-frequency harmonics from the supply connection
and thus effect basic interference suppression of the supply system. These modules are
essential to the operation of Active Line Modules. The VSM10 Voltage Sensing Module also
helps Active Line Modules to operate properly when mains power conditions are less than
ideal (e.g. severe voltage fluctuations, brief interruptions in the line voltage). VSMs are
integrated as standard in the Active Interface Modules for Active Line Modules in chassis
format. The following diagram illustrates a parallel connection of Active Line Modules
(chassis format) and Motor Modules.
Drive functions
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
potential circulating currents between the parallel-connected Motor Modules (no minimum
cable lengths and no motor reactors).
modulation can be used, i.e. when the parallel connection is supplied by Basic Line
Modules or Smart Line Modules, the maximum obtainable output voltage is almost equal
to the three-phase AC line voltage connected to the infeeds (97 %). When the parallel
connection is supplied by Active Line Modules, a higher output voltage than the input
voltage at the three-phase end can be obtained due to the increased DC link voltage.
Function modules
7.11 Parallel connection of power units
333