Inboard End Only.
Motor driven through a gearbox.
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quote:Originally posted by Machine Survey:
I agree with Michael and Mascherama... I would really like to see the slow roll orbit. Would want to either confirm or rule-out whether it is a journal surface condition (ie glitch).
quote:Casing readings showing 1.5 mils, both inboard and outboard in horizontal direction
quote:There is no correct ratio of amplitude between prox probes and casing mounted accelerometer
quote:Is there any tendency toward a similar orbit shape at the opposite end?
quote:I'm guessing the 1.5 mils at 4X?
quote:Buddy... you seem, to me, to be unresponsive to any of the suggestions that the reading is due to glitch? Do you have evidence that proves otherwise? I suspect your entire "check and perform" list could possibly be dismissed if there is slow-roll evidence during the coastdown that shows a square orbit similar to the operating orbit? John gave an insightful example in which a journal was work-hardened during machining which caused abnormalities in the probe reading. I would add another "check" item to check the slow-roll orbit during the coastdown...
quote:So, are these casing readings and the probe readings (casing equaling 1/2 of the probe) seemingly real and correct as far as the movement of the shaft is concerned, and there is apparently no glitches involved, based on the readings?
quote:Originally posted by William_C._Foiles:
It looks like probes have been interchanged and a 90 degree rotation. If the probes(or if using an O'scope) this could easily occur, but this looks digital.
Look at it from the back side to change the 'orientation' or precession direction then rotate 90 degrees to get this. Or, there is something funny going on here.
Anyway this would occur if the probes were swapped on an O'scope - it does the orientation change and the rotation by 90 degrees if you like to think of it that way.
quote:Originally posted by Buddy Morris:
Just to catch up on the more recent replies,
John,quote:Is there any tendency toward a similar orbit shape at the opposite end?
The other bearing is not showing this pattern. Looks like more of a random plot with no rhyme or reason why.
See the attached plot.
I add here a simple orbit simulator from RITEC.
It allows for 3 frequency inputs (amp. and Phase), plots blank-bright/bright-blank once per rev trigger mark, accommodates different prox. probes and keyphasor orientations, and machine speed/direction of rotation can be altered. The X/Y time waveforms are also plotted.