Advanced commissioning
7.5 Motor control
Converter with control units CU250D-2
Operating Instructions, 04/2015, FW V4.7.3, A5E34261542B AB
153
7.5.2.5
Friction characteristic
Function
In many applications, e.g. applications with geared motors or belt conveyors, the frictional
torque of the load is not negligible.
The inverter provides the possibility of precontrolling the torque setpoint, bypassing the
speed controller. The precontrol reduces overshooting of the speed after speed changes.
Figure 7-20 Precontrol of the speed controller with frictional torque
The inverter calculates the current frictional torque from a friction characteristic with 10
intermediate points.
Figure 7-21 Friction characteristic
The intermediate points of the friction characteristic are defined for positive speeds. In the
negative direction of rotation, the inverter uses the intermediate points with a negative sign.
