Orbit Article

Vibration Signatures Roller Element Bearings: Before & After an Overhaul

Syed Hussain
MDS Engineer
2 Min Read
Vibration Signatures Roller Element Bearings


One of our customers was made aware of the elevated acceleration levels on the Motor in January 2019. Spectral content showed harmonics of running speed frequency with noticeable impacts in the waveform. Afterwards, the G4131A was taken out of operation but was run again in June 2019 without any intrusive work done on it.

The elevated bearing stress was initially recorded and highlighted in January however further step increase was recorded in June. (Please note that unit was not operation from January 2019 till June 2019.) In June 2019, sharp impacts were recorded in the Time Waveform during the vibration survey conducted. 

Vibration Data GM4131a Lube Oil Pump A, before and after overhauling

The demodulated spectra showed harmonics of synchronous frequency which is potentially indicative of mechanical looseness or excessive bearing wear on the Motor. The customer was advised to stop the machine and overhaul the Motor which was finally accomplished in September 2019.


Running speed harmonics in spectral content and sharp impacts in the Time Domain is normally indicative of mechanical looseness / excessive bearing wear.

Vibration Data GM4131a Lube Oil Pump A, before and after overhauling pt2


The unit was finally overhauled in September 2019 and acceleration levels came down to satisfactory levels.


  • Estimated breakdown maintenance cost saved is £20,000.
  • Bently Nevada machinery diagnostic services with reliable tools and monitoring program prevented px_limited asset from breakdown increasing availability & reliability of the machin
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