Lenze 8615E - Manual (Page 94)

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6.1.1 Automatic chopping frequency reduction
If you want to operate the frequency inverter with 4 kHz (C143 =
-2- to -6-) or a higher chopping frequency, but also require an
improved smooth running with low speeds, you can activate an
automatic chopping frequency reduction, restricted to this range.
For this, enter the output frequency under C143, below which the
chopping frequency is to be reduced automatically to 2 kHz.
When selecting the chopping frequencies "12kHz fixed"
(C018 = -7-) and "16 kHz fixed" (C018 = -8-), you must set C143
"Threshold for automatic chopping frequency reduction to 2 kHz" to
0.0 Hz. Otherwise the inverter would reduce its chopping frequency
to 2 kHz below the set threshold. This may damage or destroy
connected filters.
Code Parameter Meaning Acceptance
C143* 0.0Hz
0...10.0Hz Threshold for automatic chopping frequency reduction
to 2kHz
0.0Hz = automatic chopping frequency reduction
deactivated ON-LINE
* extended code set
6.2 Automatic DC injection braking
Under code C019 you can enter an output frequency below which
the DC injection braking is automatically active.
Code Parameter Meaning Acceptance
C019 0.0Hz
0.0...480Hz Threshold for automatic DC injection braking
0.0Hz = automatic DC injection braking deactivated ON-LINE
For further information about setting the DC injection braking see
page 79.
6.3 Slip compensation
Under load, the speed of an asynchronous machine is considerably
reduced.
You can almost eliminate this load-dependent speed reduction, also
referred to as slip, by using the slip compensation.
In a frequency range from approximately 5 Hz to V/f rated
frequency (C015), an accuracy of
∆
n/nN < 1% can be obtained.
The value to be entered under C021 is directly proportional to the
rated slip of the machine.
Code Parameter Meaning Acceptance
C021 0.0%
0.0...20 % Slip compensation
(in steps of 0.1%) ON-LINE