Siemens SINAMICS S120 - Parallel Connection of Power Units

Function modules
8.10 Parallel connection of power units
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
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8.10
Parallel connection of power units
In order to extend the power range, SINAMICS S120 supports the parallel connection of
identical power units such as Line Modules and/or Motor Modules. The prerequisites for
connecting power units in parallel are as follows:
● Same type
● Same type rating
● Same rated voltage
● Same firmware version
● Chassis or cabinet format
● The Motor Modules must be operated in vector control
It makes sense to connect Line Modules and Motor Modules in parallel for the following
reasons:
● To boost the converter output if it is not technically or economically feasible to achieve the
required power by any other means.
● To increase the availability, for example, to maintain emergency operation (possibly also
at a lower rating), if a power unit fails.
Parallel operation is not released under the following conditions:
● Combining different types of Infeed Module within the same parallel connection (e.g.
Basic Line Modules with Smart Line Modules or Basic Line Modules with Active Line
Modules).
● Motor Modules in servo control
● Infeed Modules and Motor Modules in the booksize and blocksize formats