Danfoss VLT FC 102 Instruction Manual page 53

Diagnostics and Troubleshoo...
Symptom Possible cause
Adjustable Motor data are entered
frequency incorrectly
drive
deceleration
problems
Acoustic noise
or vibration
(e.g., a fan
blade is Resonances, e.g., in the
making noise motor/fan system
or vibrations
at certain
frequencies)
Table 7.7 Troubleshooting
®
VLT HVAC Drive Instruction Manual
Test
If warnings or alarms occur, see 7.3 List of
Warnings and Alarms.
Check that motor data are entered correctly
Bypass critical frequencies by using
parameters in parameter group 4-6* Speed
Bypass
Turn off overmodulation in 14-03 Overmodu-
lation
Change switching pattern and frequency in
parameter group 14-0* Inverter Switching
Increase Resonance Dampening in
1-64 Resonance Dampening
MG11AJ22 - Rev. 2013-09-13
Solution
Increase the ramp-down time in 3-42 Ramp
1 Ramp-down Time. Enable overvoltage
control in 2-17 Over-voltage Control.
Check if noise and/or vibration have been
reduced to an acceptable limit.
7 7
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