Imbalance Vibration-Spectra
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morgan-bridges -
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Transcript of Imbalance Vibration-Spectra
Static&Imbalance-
• Also%known%as%forced%imbalance%2• Weight%distribution%axis%parallels%the%rotational%axis.2• Occurs%when%a%heavy%spot%is%located%at%the%mid>point%between%the%bearings.%2• More%common%in%rotors%that%are%short%compared%to%diameter.%22
Couple&Imbalance-
• 180°%out>of>phase%on%same%shaft2• 1X%always%present%and%dominates%the%spectrum%2• Amplitude%varies%with%square%speed.2• Weight%distribution%axis%intersect%the%rotational%axis2• Correction%requires%the%balance%weights%in%at%least%2%planes.%22
Dynamic&Imbalance-
• Also%known%as%quasi>static%imbalance%2• Most%common%imbalance2• Occurs%when%the%rotational%axis%and%the%weight%distribution%axis%do%not%intersect%at%all.%2• A%combination%of%static%and%couple%imbalances%2
Overhung%Imbalance-
• 1X%radial%and%axial%vibrations2• Radial%signals%are%because%of%bending%effects2• Axial%readings%might%be%unsteady2
1X:$$$Radial$
RPM$
Amplitu
de$$
1X:$$$Radial$
RPM$
Amplitu
de$$
1X:$$$Axial$&$Radial$
RPM$
Amplitu
de$$
1X:$$$Radial$
RPM$
Amplitu
de$$
$