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[econk]

Anyone seen this on one of their motors? This is on the OD surface of the outer race. Identical markings are on the bearing housing. The splotched are textured, it kind of looks like spalling, but there are no other indications of relative motion between the bearing and the housing. The housing fit measured good, and so did the bearing fit on the shaft. Any ideas?

 

[Strong]

What was the condition of the ID surface and other surfaces of inner race and rolling elements? Does the motor have VFD for variable speed?

Walt

 

[econk]

Both raceways were smooth, as well as the inner race ID surface. No other damage on the bearing except for the OD surface. It is driven by a VFD, but there’s no frosting or fluting on either raceways or bearing balls, so I don’t believe it to be shaft currents.

 

[Strong]

So what was the reason for removing a perfectly good bearing?

Walt

 

[econk]

We're a motor repair shop. When we disassemble a motor, we take off the bearings and inspect them for damage. This helps to determine the failure mode and mitigate the issue so it won't fail again.

 

[electricpete]

That's very odd.

1 First thought is a shade tree mechanic did it to improve the fit (similar to peening in the old days). But no, the lines are too straight/perpendicular to have been done by handtools.

2 Second thought - somehow (lord only knows how) the lines formed at the location of the rolling elements. But no, I sincerely doubt this scenario. I'll ask anyway: are these cylindrical roller bearings? Does the line spacing resemble the roller spacing?

3 Third thought. Some or all of the marks occurred assembly (or previous disassembly / assembly in case of the housing). Possibly some abrasive debris was trapped between the two. (how did both surfaces get damaged: 3A some particles stuck on bearing and damaged housing while other particles stuck on housing and damaged bearing; 3B a given particle may have slid along one surface until it caught/stopped, causing damage to the other). I notice at least 3/4 lines go all the way to bottom of photo but not to the top... I assume top side of bearing faces shaft shoulder? I'll bet the housing bore lines extend only over part of the axial distance also.

It seems to me the most plausible of above scenario's is the third. Photos of housing damage might give fodder for further speculation.


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(2B)+(2B)' ?

 

[Skogsgurra]

It would be interesting to know the make and the type, including all numbers and letters, of this bearing. It may open up the "fodder bin" even more.

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.