VLT
®
4000 VT
until the frequency has been achieved at which
the motor is as quiet as possible.
NOTE
Switching frequencies higher than 4.5
kHz implement automatic derating of the
maximum output of the AFD. See
Derating
of high switching frequency
.
408 Interference reduction method
(NOISE REDUCTION)
Value:
✭
ASFM (ASFM)
[0]
Fixed switching frequency
(FIXED SWITCHING FREQ.)
[1]
LC filter fitted (LC-FILTER CONNECTED)
[2]
Function:
Used to select different methods for reducing the
amount of acoustic interference from the motor.
Description of choice:
ASFM
[0] guarantees that the maximum switching
frequency, determined by parameter 407, is used
at all times without derating of the AFD. This is
done by monitoring the load.
Fixed switching frequency
[1] makes it possible to set a
fixed high/low switching frequency. This can generate
the best result, as the switching frequency can be set
to reduce acoustic noise in the motor. The switching
frequency is adjusted in parameter 407
Switching
frequency
.
LC-filter fitted
[2] is to be used if an LC-filter
is fitted between the AFD and the motor, as the AFD
will otherwise not be able to protect the LC-filter.
409 Function in case of no load
(FUNCT. LOW CURR.)
Value:
Trip (TRIP)
[0]
✭
Warning (WARNING)
[1]
Function:
This function is activated when the output current goes
below parameter 221
Warning: Low current.
Description of choice:
In the case of a
Trip
[1], the VLT AFD will stop the motor.
If
Warning
[2] is selected, the VLT AFD will give a
warning if the output current drops below the threshold
value in parameter 221
Warning: Low current, I
LOW
.
Parameter 410 and 411:
NOTE
Par. 410 and 411 are not available for
VLT 4042-4062 200-240 V, and VLT
4100-4600 380-460 V.
410 Function at line failure
(MAINS FAILURE)
Value:
✭
Trip (TRIP)
[0]
Autoderate & warning
(AUTODERATE & WARNING)
[1]
Warning (WARNING)
[2]
Function:
Select the function which is to be activated if the line
imbalance becomes too high or if a phase is missing.
Description of choice:
At
Trip
[0] the AFD will stop the motor within a few
seconds (depending on drive size).
If
Autoderate & warning
[1] is selected, the drive
will export a warning and reduce the output current
to 30 % of I
VLT,N
to maintain operation.
At
Warning
[2] only a warning will be exported when
a line failure occurs, but in severe cases, other
extreme conditions might result in a trip.
NOTE
If
Warning
has been selected, the life
expectancy of the drive will be reduced
when the line failure persists.
NOTE
At phase loss the cooling fans of NEMA 12
drives cannot be powered. In order to avoid
overheating, an external power supply can
be connected, see
Electrical installation
.
411 Function at overtemperature
(FUNCT. OVERTEMP)
Value:
✭
Trip (TRIP)
[0]
Autoderate & warning
MG.40.A7.22 - VLT is a registered Danfoss trademark
98
