Siemens SINAMICS S120, Function Manual

Page: 425 / 1094

Basic functions
7.29 Parallel connection of motors
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
425
7.29 Parallel connection of motors
For simple commissioning of group drives (a number of identical motors operating on one
power unit), the number of parallel-connected motors can be entered via STARTER (only for
vector control) or via the expert list (for servo and vector control) (p0306).
An equivalent motor is computed internally depending on the number of motors specified.
The motor data identification determines the data for an equivalent motor. For a parallel
connection, operation with encoder (at the 1st motor) is also possible.
Note
For information about parallel connection of Motor Modules, see Section "Parallel connection
of power units (Page 559)".
Features
● Up to 50 motors connected in parallel can be operated on one frequency converter.
● The original motor data set (p0300 ff.) is not modified. It is merely the data set transfer to
the closed-loop control which is organized according to the number of parallel-connected
motors.
● The stationary motor data identification also works for parallel connections.
● The rotating measurement function also works if the motors can rotate without distance
limit. Uneven loading of the motors or a high degree of gear backlash will negatively
affect the accuracy of the rotating measurement result.
● The cable lengths for motors connected in parallel must be as symmetrical as possible to
afford the most even possible distribution of current among individual motors.
● Motors connected in parallel with servo control, must be individually thermally monitored.
Synchronous motors connected in parallel must have the same EMF so that no unwanted
currents flow between the motors.
Commissioning via STARTER for vector control
Note
Motors with servo control can only be connected in parallel via the expert list.