VibrationandNoise

Mostnoiseandvibrationproblems
arecausedbycomponentsbeing
worn,misaligned,orloose.These
conditionscanusuallybefoundby
observation.Theproblemissolved
byreplacement,realignmentor
tighteningofthepartsinvolved.

OtherNoiseandVibration

Sources

1. Wheelunbalanced
2. Drivecomponentsunbalanced
3. Bearingdefective,contaminated
ornotlubricatedadequately
4. Setof“unmatched”beltsinuse
5. Foreignmaterialinfanhousing
6. Electricalhumfrommotor
7. Airvelocityhigherthandesign
8. Fanoperatinginsurge
9. Isolationsystemnotfunctioning
properly
10.Shaftbent

HPTooHigh

1. Fanspeedabovedesign
2. Staticpressureabovedesign

LowCFM

1. Leaksorobstructionsinduct
system
2. Accessdooropen
3. RPMtoolow
4. Systemresistancehigherthan
design
5. Variableinletvanespartially
closed

HighCFM

1. Systemresistancebelowdesign
2. RPMtoohigh

OverheatedBearing

Bearingsonhighspeedfanscanrun
ashighas75°Faboveambient.
Theymayfeelverywarmwithno
problembeingpresent.Thisis
especiallytrueimmediatelyafter
lubricationwhenitisnormalfor
bearingstorunsomewhathotwhile
theypurgeexcessgrease.

HighTemperatures

Abnormallyhightemperaturescan
becausedbythefollowing
conditions:
1. Overgreasing
2. Foreignmaterialinbearing
3. Excessivebelttension
4. Pooralignment
5. Bentshaft
6. Damagedorwornbearing
7. Inadequatelubrication
30 QFNA-IOM-1
Troubleshooting