PeakVue revealed peaks matching FTF. No any other signs in normal, such as ball defect modulated by cage, or in peakvue data is present.

As you can see not all cursors match FTF peaks. Also peakVue amplitude is kind of high. All I can think of is lack of lubrication which manisfested itself as friction in the cage modulated by the cage friquency.
Any other opinions?
Thanks,
Dave

Cage_PeakVue.doc (69 Kb, 110 downloads)

Try autocorrelating the waveform. It will remove the random energy and you can approximate the amount of energy in the waveform coming from the periodic activity. If the autocorrelation value is low, most of the high amplitude peaks in the waveform is probably from lubrication problems. Post the autocorrelated waveform with harmonic cursors on cage frequency.

Provide me the details
Temperature of the Lube oil.
Color of the Lube.
Lube oil properties...

Jim,

Attached is the autocorrelation plot. I have observed even before that there is no any FTF in there clearly standing out. As a matter of fact nothing in the autocorrelation plot is standing out. So, according to the rules, there is only non-periodic signal present (which could be attributable to lubrication).

But this scenario exactly constitues a problem that I can see with autocorrelation, namely: in presence of high noise, a small although periodic signal may be in there
(like in this case) but of low value causing underestimation.

This is a grease lubed bearing.

Dave

Cage_PeakVue.doc (78 Kb, 58 downloads)

Dave,
This looks like a lube fault. I usually monitor the PeakVue waveform while adding a small amount of grease. Usually the waveform amplitude bottoms out immediately if there is a lube problem. I often see cage frequency with a lube fault in PeakVue data. The autocorrelated waveform will usually indicate little or no periodic energy (as in your case) or mounds (modulation) spaced at cage frequency. If there are sharp peaks spaced at cage there is more likelihood of an actual cage defect.

Dave, can you lubricate the bearing and re-take the Peak-Vue?