KEB COMBIVERT F5 BASIC Applications Manual page 174

Functional Description
Fig. 6.5.5.c Example: Deceleration of a centrifugal-load drive from 80Hz
Actual frequency
DC-link voltage
Motor voltage
Load
6.5.6 Maximal voltage
mode (uF.10)
6.5.7 Switching
Frequency (uF.11)
Chapter Section Page
6 5 6
with voltage stabilization
By changing the maximal voltage mode more torque can be releasedfree above the
rated frequency through overmodulation (110% voltage). Raising the U/f-characteristic
has an influence at activated energy saving function or at voltage stabilization.
uF.10 Modulation
0 100 % U/f / 100% voltage
1 110 % U/f / 110% voltage
2 200 % U/f / 100% voltage
3 200 % U/f / 110% voltage
The switching frequency with which the power modules are clocked, can be changed
depending on the application. The maximal possible switching frequency as well as
the factory setting are determined by the employed power circuit.
uF.11Switching frequency
Combivis Display/Plaintext
0
1
2
3
4
The current switching frequency is indicated in the parameter ru.45, the max. switching
frequency in In.3 and the switching carrier frequency in In.4.
Date Name: Basis
17.04.02 KEB COMBIVERT F5
U/f-Characteristic Adjustment
Actual frequency
DC-link voltage
Motor voltage
Load
Description
without overmodulation; all limitations 100% of
modulation factor
with overmodulation; all limitations 110% of
modulation factor
limitations between voltage-forming functions
200%; limitation before modulator 100% of
modulation factor
limitations between voltage-forming functions
200%; limitation before modulator 110% of
modulation factor
Frequency
2 2 kHz
4 4 kHz
8 8 kHz
12 12 kHz
16 16 kHz
without voltage stabilization
At switching frequencies
above 4 kHz absolutely
consider the max. motor line
length specified in chapter
2.1.6 and 2.1.7.
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