Danfoss VLT FC 302 Operating Instructions Manual page 140

Basic Start-up Troubleshoot...
Symptom
Acoustic noise or vibration
(e.g. a fan blade is making
noise or vibrations at
certain frequencies)
Table 10.1 Troubleshooting
10 10
138
Operating Instructions
Possible cause
Resonances, e.g. in the motor/fan
system
Danfoss A/S © Rev. 2014-07-29 All rights reserved.
Test
Bypass critical frequencies by using
parameters in parameter group
4-6* Speed Bypass
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
Solution
Check if noise and/or vibration
have been reduced to an
acceptable limit
MG37A202