KEB COMBIVERT F5-A, Applications Manual, Page: 236 / 552

Page 7.7 - 10 COMBIVERT F5-A, -E, -H © KEB, 2012-10
Speed control
7.7.4.1 Precontrol reciprocal of amplification / filtering
For some applications it is not necessary to pre-control the complete acceleration torque (cS.28 = 100%) see
the following reasons:
- a different torque is required with the same acceleration at motoring or generating (e.g. due to friction)
- the speed setpoint setting (e.g. by external control) is made in steps, so torque jumps can occur
- the (analog) speed setpoint setting is superimposed by a noise, which must be damped for the pre-
control
The influence of the pre-control can be damped with parameter cS.28
„pretorq. speed fact. %" for these appli-
cations
Torque peaks, which are caused by a speed setpoint setting in steps, can be reduced by means of a low
pass filter. Here also valid: the higher the time in parameter cS.27 „
pretorq. speed PT1 time“ the better the
smoothing, the undynamic but also the precontrol.