Vibration data for Shaft Misalignment - Angular and Offset

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 Vibration Data for Shaft  Misalignment 

Offset/Parallel Misalignment 1X,2X,3X & sometimes 4X & 5X in the radial direction at Motor Running Speed, RPM




Angular Misalignment: 1X & 2XRPM in the axial direction. 1X,2X & sometimes 3X in the radial direction. This can depend on the type of coupling in service.




Offset/Parallel Misalignment The Centerlines are parallel but offset. 



Offset Misalignment Spectrum. Be aware 3X & 4X RPM also be present. Note the 180 deg out of phase across the Coupling

This is why phase measurements are needed to help confirm parallel misalignment. The 2X RPM is usually higher than 1X RPM. Readings taken radially in the horizontal and vertical planes should be similar.

Angular Misalignment Spectrum: Basically stated, angularity is the gap difference across two coupling faces-normally top to bottom or side to side.


Angular misalignment in the radial direction

Spectrum: Angular misalignment produces a bending moment on each shaft, and this generates a strong vibration at 1X and some vibration at 2X in the axial direction at both bearings. There may also be a 1X,2X  & possible 3X in the radial direction.


Note approximately a 180 deg phase shift across the coupling in the axial direction.


Recommended Corrective Action
 If coupling misalignment is diagnosed then a notification to be raised to rectify at the next available opportunity. Accurate shaft alignment will reduce axial and radial forces increasing bearing life.

Contacts

Email: robbieccs@gmail.com

Stay safe 

Cheers

Robert 








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