Siemens SINAMICS G120 Operating Instructions Manual page 375

Droop (P1488 ... P1492)
The droop (enabled using P1488) means that with increasing load torque, the speed setpoint
is proportionally reduced.
Figure 8-94
Droop is the simplest method to implement load sharing control. However, this load sharing
control can only be used if the motors are operated more or less under steady-state
conditions (i.e. at constant speed). For motors, which are frequently accelerated and braked
with high speed changes, this technique is only conditionally suitable.
The most simple load sharing control is, e.g., used for applications where two or several
motors are mechanically coupled or operate on a common shaft and which have to fulfill the
requirements above. In this case, the droop controls torsional stressing associated with the
mechanical coupling by changing the speeds of the individual motors (excessive torques are
reduced for an individual motor).
Prerequisite
● All of the motors must be operated with closed-loop Vector speed control (with or without
● The ramp-up and ramp-down times of the ramp-function generator must be identical for
Control Units CU240S
Operating Instructions, 11/2006, A5E00766042B AA
Speed controller with droop
speed actual value encoder)
all of the motors.
8.24 Open-loop and closed-loop control
Functions
8-179