Danfoss VT2800 Series Design Manual page 98

411 Switching frequency
(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 converter
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 parameter
412, the minimum switching frequency is 4.5 kHz.
412 Variable switching frequency
(VAR CARRIER FREQ.)
Value:
Without LC-filter (WITHOUT LC-FILTER)
LC-filter connected
(LC-FILTER CONNECTED)
Function:
The parameter must be set to LC-filter connected
if an LC-filter is connected between the frequency
converter 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.
NB!:
When the LC filter is selected the switching
frequency is changed to 4.5 kHz.
= factory setting. () = display text [] = value for use in communication via serial communication port
98
413 Overmodulation function
(OVERMODULATION)
Value:
Off (OFF)
4500 Hz
On (ON)
4500 Hz
Function:
This parameter allows connection of the
overmodulation 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 feature, 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
(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
minimum feedback signal value on the selected
feedback input (parameters 308/314 Analogue inputs).
[2]
[3]
415 Maximum feedback, FB
(MAX. FEEDBACK)
Value:
FB - 100,000.000
MIN
Function:
See description of parameter 414 Minimum
feedback, FB
Description of choice:
Set the value to be shown on the display when the
maximum feedback has been obtained on the selected
feedback input (parameter 308/314 Analogue inputs).
MG.28.E9.02 - VLT is a registered Danfoss trademark
®
VLT 2800 Series
MIN
MAX
MIN
are used to scale the
MAX
MAX
.
MIN
[0]
[1]
0.000
and 415
1500.000