Feedback; Overmodulation Function - Danfoss VLT 2800 Series Operating Instructions Manual

delay overcurrent, I is not working, i.e. disconnec-
LIM
tion will not take place.
411 Switching frequency
411
(SWITCH FREQ.)
Value:
3000 - 14000 Hz (VLT 2803 - 2875)
3000 - 10000 Hz (VLT 2880 - 2882)
Function:
The set value determines the switching frequency of
the inverter. If the switching frequency is changed,
this may help to minimise possible acoustic noise
from the motor.
NB!:
The output frequency of the frequency con-
verter can never assume a value higher than
1/10 of the switching frequency.
Description of choice:
When the motor is running, the switching frequency
is adjusted in parameter 411 Switching frequency
until the frequency has been obtained at which the
motor is as low-noise as possible.
NB!:
The switching frequency is reduced
automatically as a function of the load. See
Temperature-Dependent Switching Frequency under
Special Conditions.
When LC-filter connected is selected in pa-
rameter 412, the minimum switching frequency is 4.5
kHz.
412 Variable switching frequency
412
(VAR CARRIER FREQ.)
Value:
Without LC-filter (WITHOUT LC-FILTER)
LC-filter connected
(LC-FIL TER CONNECTED)
Function:
The parameter must be set to LC-filter connected if
an LC-filter is connected between the frequency con-
verter and the motor.
Description of choice:
The LC-filter connected [3] must be used if an LC-
filter is connected between the frequency converter
and the motor, as otherwise the frequency converter
cannot protect the LC-filter.
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.A5.02 - VLT is a registered Danfoss trade mark
®
VLT 2800 Series
NB!:
When the LC filter is selected the
switching frequency is changed to 4.5 kHz.

413 Overmodulation function

413
(OVERMODULATION)
Value:
4500 Hz
Off (OFF)
4500 Hz
On (ON)
Function:
This parameter allows connection of the overmodu-
lation function for the output voltage.
Description of choice:
Off [0] means that there is no overmodulation of the
output voltage, which means that torque ripple on
the motor shaft is avoided. This can be a good fea-
ture, e.g. on grinding machines.
On [1] means that an output voltage can be obtained
which is greater than the mains voltage (up to 5 %).
414 Minimum feedback, FB
414
(MIN. FEEDBACK)
Value:
-100,000.000 - par. 415 FB
Function:
Parameter 414 Minimum feedback, FB
Maximum feedback, FB
display text to make it show the feedback signal in a
process unit proportionally to the signal on the input.
Description of choice:
Set the value to be shown on the display as the min-
imum feedback signal value on the selected
feedback input (parameters 308/314 Analog inputs).
[2]
[3]
415 Maximum feedback, FB
415
(MAX. FEEDBACK)
Value:
FB - 100,000.000
MIN
Function:
See description of parameter 414 Minimum feed-
back, FB .
MIN
Description of choice:
Set the value to be shown on the display when the
maximum feedback has been obtained on the se-
MIN
0.000
MAX
and 415
MIN
are used to scale the
MAX
MAX
1500.000
[0]
[1]
41