66
407
Switching Frequency
(SWITCHING FREQ.)
Value:
Depends on the current rating of the unit.
Function:
The value of this parameter determines the maximum switching
frequency of the inverter. If
Fixed Switching Frequency
has been
selected in parameter 408,
Interference Reduction Method,
this will be
the fixed inverter switching frequency. Changing the switching
frequency may reduce audible noise from the motor. The output
frequency of the drive can never be a greater than 1/10 of the
switching frequency.
Description of choice:
When the motor is running, the switching frequency may be adjusted
by parameter 407,
Switching Frequency,
until the sound level is as low
as possible.
Switching frequencies higher than 4.5 kHz will result in automatic
derating of the maximum continuous output current of the drive. The
derate is linear from 4.5 kHz to the maximum switching frequency of the
drive. At maximum switching frequency, the continuous output current
from the drive will be limited to 60% of the rated current. To avoid
possible problems at high load when using a high switching frequency,
it may be desirable to select Automatic Switching Frequency Modulation
in parameter 408, below.
NOTE
Switching frequencies higher than 4.5 kHz
automatically derate maximum continuous
output of drive.
408
Interference Reduction Method
(NOISE REDUCTION)
Value:
★
ASFM (ASFM)
[0]
Fixed switching freq. (FIXED SWITCHING FREQ.) [1]
LC filter fitted (LC-FILTER CONNECTED)
[2]
Function:
Used to select different methods for reducing the amount of audible
noise from the motor.
Description of choice:
ASFM (Automatic Switching Frequency Modulation)
uses the
maximum switching frequency possible while providing the output
required by the load. The load is automatically monitored and the
switching frequency set accordingly. The maximum switching frequency
is set in parameter 407,
Switching Frequency
.
Fixed Switching Frequency
makes it possible to set a fixed switching
frequency. The switching frequency is set in parameter 407,
Switching
Frequency.
LC-filter fitted
is to be used if an LC filter is installed between the drive
and the motor. This prevents excessive heating of the LC filter.
409
Function in Case of No Load
(FUNCT. LOW CURR.)
Value:
Trip (TRIP)
[0]
★
Warning (WARNING)
[1]
Function:
This parameter can be used for monitoring the V-belt of a fan or other
power transmission component to make sure it has not broken. This
function is activated when the output current goes below the current level
set in parameter 221,
Warning: Low Current
. This function is not active
during a start until the drive has reached the speed reference. It is also
not active while the drive is stopped or while it is decelerating to a stop.
Description of choice:
In the case of a
Trip
, the drive will stop the motor if the output current
drops below the value set in parameter 221.
If
Warning
is selected, the drive will give a warning if the output current
drops below the value set in parameter 221.
✭
I
ndicates factory default setting. Numbers in brackets [ ] represent selection as displayed on the serial bus.
