KEB COMBIVERT F5-A, Applications Manual, Page: 250 / 552

Page 7.8 - 12 COMBIVERT F5-A, -E, -H © KEB, 2012-10
Torque display and -limiting
voltage by parallel shifting of the corner can not optimally reflect the reality.
A further possibility of limitation can occur by the evaluation of voltage equation. The equation is converted to
isq and the max. permissible voltage is preset for the voltage component usd.
L
sq
= Inductance in the Q-axis (dr.64)
R
s
= stator resistance (dr.30)
f = output frequency (ru.03)
Uic
Ref
= Reference for the maximum voltage controller (dS.10)
Ud
Ref
= Factor voltage component Usd (dS.37)
usd
Ref
=
Uic
Ref
*
Ud
Ref
*
Uic
100% 100%
√6
isq
max
=
Rs * isd - usd
max
2 *
π
* f * Lsq
Since it is calculated with equivalent circuit diagrams in the formula, deviations can occur in
case of different temperatures or as a function of the saturation (Lsq) of the inductance.
7.8.4 Adjustmentof application-dependent torque limits
For some applications it is not required to provide the maximum possible torque, but the application requires
other process-related limitations (e.g. to protect mechanical components).
These can be adjusted via parameters cS.19...cS.23. The
torque limiting characteristic which is defined by
maximum current and available voltage remains always active as superior limit.
If only one limit is required for all operating ranges (forward, reverse, motorized and regenerative), parameter
"absolute torque setpoint" (cS.19) can be used therefore. All other limits (cS.20...cS.23) must be set to value
„-1:off“.
If different torque limits are required, these must be entered in parameters cS.20...cS.23 (= torque limit for the
different operating ranges).
The torque limits can be adjusted during operation for special applications by multiplying with a factor of
0...100%.
Parameter " torque reference source" (cS.15) determines how this factor is built for the adjusted torque limits
(cS.19...cS.23).
cS.15: Torque reference source
Value Explanation
0: analog REF Parameter „Selection REF-input / AUX function“ (
An.30) defines, how the Ref- or Aux-value
is calculated (see chapter 7.2). As standard AN1 is the Ref-value and AN2 the Aux-value.
They are limited to 100% as multiplier for the torque limit (s).
1: analog Aux
2: digital absolute
(cS.19..23)
the torque limits (cS.19...cS.23) are not reduced with a factor
3: digital % (cS.18)
cS.18 (percentage torque reference) is the factor for the torque limits
(cS.19...cS.23)
4: Motorpoti
(ru.37) the output value of the motorpoti function (see section 7.15) is the factor for the torque
limits (cS.19...cS.23)