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In vibration spectrum,1x means the RPM. with Angular misalignment bearing always rocks1 time in1 rotation that gives a vibration of the same frequency of RPM that means1X but when it comes to parallel misalignment, then the bearing have two times rocking motion from0 deg to deg i.e.1 rotation of shaft. and therefore it vibrates with double frequency then rotation and we observe2X in vibration spectrum.
Bearing Misalignment is also called as cocked bearing.in this case, it will show dominant 2 X in axial direction. axial phase readings are also good indicator on the same bearings (0,90,180,270) top to bottom or side to side will be 180 deg phase difference if the bearing is cocked.
there is two kind of misalignment:
Angular misalignment causes axial vibration at the running speed frequency (1x).
Parallel misalignment produces radial vibration at twice the running speed frequency (2x).
Since most misalignment is a combination of angular and offset, both the radial and axial measurements’ 1x and 2x frequencies
Theoretically there are two types of misalignment. Parallel and angular. In both we have a phase shift of 180 degrees. In parallel misalignment we have a relevant peak at 2X, and in the angular misalignment a peak reaches 1X.
here will be 2x frequency in the spectrum
bearing misalignment symptoms in spectrum is 1X and may be 2X appear however you have to confirm this malfunction by phase readings .
In parallel misalignment we have a relevant peak at 2X with a phase shift of 180 degrees, and in the angular misalignment a peak reaches 1X.
it shows as 1,2and3X of rotating speed and in wave form as MW sign
There are two type of misalinment effects the bearing life to increase the load/stress on the bearings.
1. Offset Misalignment
High 1X and High 2X radial vibration (3X, 4X, 5X are also high). 180 degree radially on components on either side of coupling
2.Angular Misalignment
High 1X axial vibration. 180 degree axialy on components on either side of coupling
Bearing Misalignment cause high Axial Vibration, 2 X may be present. Temperature of bearing increases in opeartion.
Phase change in the axial direction observed when measured in the same bearing location.
This is called Cocked bearing , it is a mounting issue
angular mis alignment 1X at axial
Parallel mis alignment 2X at radial
phase should be 180 deg
