5.2.6 Acoustic Noise
The acoustic noise from the frequency converter comes from two sources:
1.
DC intermediate circuit coils.
2.
Inverter.
Below are the typical values measured at a distance of 1 m from the unit at full load:
FCD 303-335 3 x 400 V: 52 dB(A).
5.2.7 Derating for Ambient Temperature
The ambient temperature (T
AMB,MAX
) is the maximum temperature allowed. The average (T
AMB,AVG
) measured over 24 hours, must be at least 5 °C lower.
If the frequency converter operates at temperatures above 40 °C, a derating of the rated output current is necessary.
FCD 303-305 +10 °C
FCD 307 +5 °C
FCD 335 -5 °C
5.2.8 Temperature-Dependent Switch Frequency
This function ensures the highest possible switch frequency without the
frequency converter becoming thermally overloaded. The internal tem-
perature is the actual expression of the degree to which the switch
frequency can be based on the load, the ambient temperature, the supply
voltage and the cable length.
The function ensures that the frequency converter automatically adjusts
the switch frequency between f
sw,min
and f
sw, max
(parameter 411), see
drawing below.
5 All About FCD 300
VLT
®
Decentral FCD 300 Design Guide
128
MG.90.S1.02 - VLT
®
is a registered Danfoss trademark
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