VLT
®
2800 Series
411 Switching frequency
(SWITCH FREQ.)
Value:
3000 - 14000 Hz (VLT 2803 - 2875)
✭ 4500 Hz
3000 - 10000 Hz (VLT 2880 - 2882)
✭ 4500 Hz
Function:
The set value determines the switching frequency of the
inverter. If the switching fre quency 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 conne cted is selected in parameter
412, the minimum switching frequency is 4.5 kHz.
412 Variable switching frequency
(VAR CARRIER FREQ.)
Value:
✭Without LC-filter (WITHOU T LC-FILTER)
[2]
LC-filter connected
(LC-FILTER CONNECTED)
[3]
Function:
The parameter must be set to LC-filter connected
if an LC-filter is connected betwe en the frequency
converter and the motor.
Description of choice:
The LC-filter connected [3]mustbeusedifan
LC-filter is connected betwee n the frequency
converter an d 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.
413 Overmodulation function
(OVERMODULATION)
Value:
Off (OFF)
[0]
✭On ( ON )
[1]
Function:
This parameter allows connection o f 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 m ains voltage (up to 5 %).
414 Minimum feedback, FB
MIN
(MIN. FEEDBACK)
Value:
-100,000.000 - par. 415 FB
MAX
✭ 0.000
Function:
Parameter 414 Minimum feedback, FB
MIN
and 415
Maximum feedback, FB
MAX
are used to scale the
display text to make it show t he feedback signal in a
process unit proportionally to the signal on the input.
Description of choice:
Setthevaluetobeshownonthedisplayasthe
minimum feedback signal value on the selected
feedback input (parameters 308/314 Analogue inputs).
415 Maximum feedback, FB
MAX
(MAX. FEEDBACK)
Value:
FB
MIN
- 100,000.000
✭ 1500.000
Function:
See description of parameter 414 Minimum
feedback, FB
MIN
.
Description of choice:
Setthevaluetobeshownonthedisplaywhenthe
maximum feedback has been obtained on the selected
feedback input (parameter 308/314 Analogue inputs).
✭ = factory setting. () = di splay text [] = value for use in communication via serial communicat ion port
MG.28.E9.02 - VLT is a registered Danfoss trademark
98
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