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Sr. Member / Supporter
Posts: 183
Reply with quote  #16 
Are you using a speedvue? Maybe the speed changed during the data collection?

In the TWF you cannot see the BPFO either?

Sr. Member
Posts: 1,918
Reply with quote  #17 
Well fluting specially VFD hi freq. related that this looks like do sometimes only give higher general bearing condition values that sums the noise and also those may have a fast initial increase and then keep that high level for a long time, months and then suddenly w/o further warning have a spectacular fail when I think the hardened surface is finished. I think there are no bearing fault freq's since there are no damage to create them it is only a surface damage.
Good Vibrations since early 1950's, first patented vibrometer 1956 in the US.
P Hine

Posts: 47
Reply with quote  #18 
Well, I guess it will remain one of those unexplainable mysteries. It just seemed strange that the fault frequencies were not more plainly visible. The 10600 cpm just doesn't line up yet it disappeared after the bearing change. Even doing an autocorrelation the peaks were right on that 10600 cpm. We have VFD cable pulled to these motors and have installed a SGS grounding system on the ODE. I am going to have a SGS split ring installed on the drive end as soon as it arrives. Hopefully we can end the fluting issue. Thanks for everyone's input. Some times you just need another set of eyes on the problem.


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Posts: 1,810
Reply with quote  #19 
Thanks for the update on this.  I haven't dug into the fault frequencies, but would just offer that fluting usually "sounds horrible" but is usually not really as bad (mechanically) as it sounds. The outer race fluting in the pics looks very shallow and unless you also see pits or spalling on the rollers, likely to run for a very long time.

For rolling-element-bearings (REB) I collect a 2kHz route spectrum (velocity) but collect a "special" timewaveform to 4kHz in acceleration.  If I 'hear' a problem, or see it in the waveform when I collect the data, then I always take extra data at a higher Fmax (6400 lines) to isolate defect frequencies, and then a high frequency waveform (10 kHz) to see "what else is out there".  And I have a parameter defined for Max Pk Waveform which gives me the maximum peak acceleration value in my standard route (special)) 4KHz waveform.  The trend of the Max Pk value is what I use to determine replacement for most REBs.

(Your mileage may vary, of courese)

"The trend is your friend"
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