Bearings - essential "as constructed" information

To my understanding, bearing details such as no. of rolling elements, dimensions of inner race, outer race and rolling elements is useful in diagnosing machinery faults through vibration analysis.

This shows the importance of recording such details in the AMS.

Is it enough to capture only bearing model nos. from the manufacturer when the rotating equipment is supplied or is it important to capture all details mentioned above.

I've heard that over time, bearing manufacturers may update their designs by changing some aspects such as the no. of rolling elements but the model nos., shaft diameter, etc. may remain unchanged. So future catalogues may not necessarily reflect what was supplied to you even if you match the model no.
Original Post
Bearing details are nice to have and I make some ridiculously lengthy efforts to get them sometimes but not really essential to good vibration analysis, imo.

To me, the only truly essential piece of information is accurate shaft speed. Without that, everything is guesswork.
In CMMS which may be like AMS, it is possible to type in all equipment data sheet but so far, it is easier to just enter the equipment model no. and refer to a booklet of all the equipment sheets which is handy. So for AMS, you might want to copy this practice to speed up the data population effort upfront.
With regards to changes in bearing details by OEM, I guess the OEM salesman should inform the client by giving the new bearing details or the person in charge should inspect the new bearing upon receipt at Store and ask for new details if any changes.
You'll never predict the exact bearing installed. It might be a bearing number on a drawing but you cannot control where it is bought from, especially the manufacturer as John from PA highlights. or what version it is.

So stick with bearing number only and use your inbuilt bearing data base to show you the permutations and combinations for the particular number. As well as this figure out which dimension series have what "frequency harmonic families" For example, 3.08x or anything very close to that tells me outer race for an 8 rolling element 63** series deep grove ball bearing. A 62** series would start at about 4.16x, a 223** close to 5.69x. Add or subtract FTF for one more or less rolling element. Other dimension series have their own frequency families. 230** 12.26x for outer race. The iso bearing number system explains all that but not many people relate it to the fault frequencies produced.

Attached is a favourite of mine to illustrate the point. For this one you can easily see there are 13, 14, 15 & 16 rolling element versions and for each version with the same number of rolling elements the FF's are close to the same - across brands as well. So no need to record all this extra stuff. Just understand where FF's come from and what are the major influencing factors, namely number of rolling elements and dimensions which are mainly related to different dimension series. rgds


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