5 months ago this gearbox was installed with new bearings. From the start there were roller spin frequencies present. So we let that go to be watched. Just now, the outer race frequencies have popped up strongly. Overall levels near 6.0 g's. Some individual fault freqs are above 2.0 g's pk. Velocity shows some harmonics with good amplitudes aproaching .2 in/s pk. Spike energy is rising (3.0 gse)and shows the harmonics.

Is it normal for roller defect freqs. to show up on new brgs (timken brg na329121)?
Timken says not unusual if they are ground roller body class 4!

They also say OR freqs may being influenced by running speed harms.?

Another opinion came in and said "This vibration spectrum may even not suggest that the
out racer of the subject bearing has pitting, spalling or cracking" I mentioned overloading. They said that also may not be the source.

Ok, then what else could cause a sudden large increase in outer race freqs(following the presence of roller freqs)?

He mentioned the word excitation for some reason??

Am I missing something in understanding vibration? Does this look like a bearing going bad or what else?

This message has been edited. Last edited by: jbalko,

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Jbalko,

Do you have any Gse spectra?
There certainly looks like some bands around most of the peaks in the second spectrum. Are they in fact sidebands, and what is the delta on them?

Thats a serious spike trend, although there may be other explanation for that, that's why I would be interested in the spectrum.

Dave

Do you have TWF? Kind of appears to be generated from some loading. And, I would take no action based on the data you presented. Future surveys on regular frequency will tell the story. But, TWF could help. For simplicity can you present your g's in Hz and S?

The gse spectra does show or freqs. I will try and add plots later. Im not sure I set up the waveform well but will try and show some or get better examples.

Sidebanding is at 1x rpm