3.10 Main Menu - Special Functions - Group
14
3.10.1 14-0* Inverter Switching
14-01 Switching Frequency
Select the inverter switching frequency. Changing the switching
frequency can help to reduce acoustic noise from the
compressor.
Option:
Function:
NOTICE
The output frequency value of
the frequency converter must
never exceed 1/10 of the
switching frequency. When the
compressor runs, adjust the
switching frequency in
parameter 14-01 Switching
Frequency
until the compressor
is as noiseless as possible.
NOTICE
High switching frequencies
heat the frequency converter
and may reduce its lifetime.
NOTICE
Not all options are available in
all power sizes.
[0]
Ran3
3 kHz true random PWM (white
noise modulation).
[1]
Ran5
5 kHz true random PWM (white
noise modulation).
[2]
2.0 kHz
[3]
3.0 kHz
[4]
4.0 kHz
[5]
5.0 kHz
[6]
6.0 kHz
[7]
8.0 kHz
[8]
10.0 kHz
[9]
12.0 kHz
[10]
16.0 kHz
14-03 Overmodulation
Option:
Function:
[0]
Off
Selects no overmodulation of the
output voltage to avoid torque
ripple on the compressor shaft.
[1]
*
On
The overmodulation function
generates an extra voltage of up to
8% of U
max
output voltage without
overmodulation, which results in an
14-03 Overmodulation
Option:
Function:
extra torque of 10–12% in the
middle of the oversynchronous
range (from 0% at nominal speed
rising to approximately 12% at
double nominal speed).
3.10.2 14-1* Mains On/Off
Parameters for configuring mains failure monitoring and
handling.
14-10 Mains Failure
Select what the frequency converter does when the mains
voltage drops below the limit set in
parameter
.
Option:
Function:
[0]
*
No function
[3]
Coasting
14-11 Mains Fault Voltage Level
Range:
Function:
Size
related
*
[100 - 800 V] This parameter defines the
threshold voltage at which the
selected function in
should be activated. The detection
level is at a factor sqrt(2) of the
value in this parameter.
14-12 Response to Mains Imbalance
Operation under severe mains imbalance conditions reduces the
lifetime of the compressor. If the compressor is operated contin-
uously near nominal load, conditions are considered severe.
When a severe mains imbalance is detected, select one of the
available functions.
Option:
Function:
[0]
Trip
Trips the frequency converter.
[1]
*
Warning
Issues a warning.
[2]
Disabled
No action.
CAUTION
May cause reduced life time.
[3]
Derate
Derates the load by mains
imbalance.
Parameters
VLT
®
Compressor Drive CDS 803
54
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MG18P202
3
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