Symptom
Possible cause
Test
Solution
Acoustic noise or vibration
(e.g. a fan blade is making
noise or vibrations at
certain frequencies)
Resonances, e.g. in the motor/fan
system.
Bypass critical frequencies by using
parameters in parameter group
4-6* Speed Bypass
.
Check if noise and/or vibration
have been reduced to an
acceptable limit.
Turn off over-modulation in
14-03 Overmodulation
.
Change switching pattern and
frequency in parameter group
14-0* Inverter Switching.
Increase Resonance Dampening in
1-64 Resonance Dampening
.
Table 9.1
Basic Troubleshooting
VLT
®
AQUA Drive D-Frame
Operating Instructions
MG21A202 - VLT
®
is a registered Danfoss trademark
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