Droop - Siemens Sinamics S120 Function Manual

Vector control

4.6 Droop

4.6 Droop
Droop (enabled via p1492) ensures that the speed setpoint is reduced proportionally as the
load torque increases.
Figure 4-12 Speed controller with droop
The droop has a torque limiting effect on a drive that is mechanically coupled to a different
speed (e.g. guide roller on a goods train). In this way, a very effective load distribution can
also be realized in connection with the torque setpoint of a leading speed-controlled drive. In
contrast to torque control or load distribution with overriding and limitation, with the
appropriate setting, such a load distribution controls even a smooth mechanical connection
or the case of slipping.
This method is only suitable to a limited extent for drives that are accelerated and braked
with significant changes in speed.
The droop feedback is used, for example, in applications in which two or more motors are
connected mechanically or operate with a common shaft and fulfill the above requirements. It
limits the torque differences that can occur as a result of the mechanical connection between
the motors by modifying the speeds of the individual motors (drive is relieved when the
torque becomes too great).
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Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2
Drive functions