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Noknroll

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Reply with quote  #16 
Pete
Believe it or not, that is normal, Its a flour sifter (shaker screen) and Velocity normal reads about 400+ mm/sec
See link.
https://www.machineryanalysis.org/post/axial-vibration-on-sifter-9688319?highlight=sifter&pid=1303635341
electricpete

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Reply with quote  #17 
Thanks Nok, I missed that "shaker" screen part. Not your ordinary machine. 

If your photo was just normal fatigue spalling, I might have suggested that ridiculously high 1x could potentially play a role. But that doesn't seem likely for the photo you posted with marks at roller spacing.  

tomcd3

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Reply with quote  #18 

Hi Nok,
Don't want to hijack your thread, but thought you might be interested.

Not so much false brinelling, but looks like heat stress while the bearing was stationary for the top one. Bottom peakvue Pk-Pk Waveform trend tops starts at 12g before we replaced, and that’s with a poor transmission path and rubber isolators in the way.

  20190104_093404.jpg  20181218_123657.jpg
Actually that looks exactly like static water corrosion damage (no heat involved); sometimes known as Black Water Etching as water and oil mix to create acids that eat into the metal. The shape of the damage is pure capillary in nature. Excellent example that should be preserved for future teachings.



tomcd3

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Reply with quote  #19 
Great catch NoknRoll!
Walt Strong

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Reply with quote  #20 
Tomcd3,

Did you confirm that pump was shutdown for quite a while with water present, or is this just a hypothesis as to cause of the visual damage?

Walt
tomcd3

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Reply with quote  #21 
My expert opinion was directed at this photo that clearly shows static water damage.

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Danny Harvey

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Reply with quote  #22 
I asked the same question early on and Nok responded that they rarely sit idle for more than a day; when they do, everything is down; and that it is a very dry environment.

I'm thinking that maybe this bearing wasn't set correctly in the axial direction and may have run quite hot.  Cooling when shut down might generate condensation within the bearing.

It sounds like a stretch to me but given Tom's educated opinion, I'm a little more confidant in my guess[smile]
tomcd3

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Reply with quote  #23 
My comments was only directed at the ACBB side discussion, NOT Nok’s SRB.
Noknroll

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Reply with quote  #24 
Walt
I got the message from client that no welding has taken place on this machine. Was worth a shot though.
tomcd3
also a good catch
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