Two adjacent fans A & B, one is running while other is standby and is interchanged periodically. Overall vibration at B is higher than A, but A has been showing bearing fault freq. and higher acceleration values.

This one looks like true brinelling, false brinelling has corrosion marks.

My opinion is installation issues, shock loads, high transmitted vibration

I agree with fburgos, installation of bearing taper lock on inner race is suspect...the taper lock should stick out both sides of the bearing, your image of the inner race shows the taper was not supporting entire inner race, if shaft is damaged this too can cause this patter on the inner race. To have 3 distinct marks closely spaced, then other marks spaced at roller spacing would suggest the bearing was slightly rotated at least twice during installation. Just my opinion

Are the fans spring isolated, any flexible boots on suction or discharge ductwork?

Dave

Thanks Dave and fburgos. This is the 3rd time in 1.5 years the bearings had to replace with similar pattern. Initially it was believed that high vibration from B fan is the culprit causing false brinelling but no formal RCFA was done. So, I asked the customer to send me the bearings to have a look and suspected about previously believed false brinelling.

The fans are spring isolated and flexible boots on suction or discharge ductwork. It was confirmed before that some vibrations are transferring from B to A but not the other way around and the ductwork was identified as the cause.

@ Sine wave,

Along the line of what Dave said about the tapered sleeve.

Why would the tapered sleeve not go completely through the bearing?

Is it possible they have the wrong sleeve. I see online where the 22211 EK-C3 takes a 1:12 taper.

If their sleeve, indeed, did not extend passed the inner race's ring it may be the wrong taper or too short (as in, one made for a bearing with a single row balls or rollers) to reach through this particular bearing.

Can you confirm that the marks showing on the inner race ring's sleeve surface in your picture were made by the tapered sleeve?

Thanks,

Ralph

@Registered Member posted:

@ Sine wave,

Along the line of what Dave said about the tapered sleeve.

Why would the tapered sleeve not go completely through the bearing?

Is it possible they have the wrong sleeve. I see online where the 22211 EK-C3 takes a 1:12 taper.

If their sleeve, indeed, did not extend passed the inner race's ring it may be the wrong taper or too short (as in, one made for a bearing with a single row balls or rollers) to reach through this particular bearing.

Can you confirm that the marks showing on the inner race ring's sleeve surface in your picture were made by the tapered sleeve?

Thanks,

Ralph

It was the right sleeve with right length tapper (H311) and I can't imagine how it could not possibly extend pass the inner race ring. ( I am not expert in mounting). Attached is the sleeve and it looks clear to me from the picture that there is an issue with mounting and wondering could it be due to wrong clearance, too tight fit/loose fit, races/rolling elements were not aligned. And, I am trying to figure out how best I could tell the mechanical people about mounting issue. It seems like a taboo to highlight any installation issue here!! Appreciate any advise!

@Registered Member posted:

It was the right sleeve with right length tapper (H311) and I can't imagine how it could not possibly extend pass the inner race ring. ( I am not expert in mounting). Attached is the sleeve and it looks clear to me from the picture that there is an issue with mounting and wondering could it be due to wrong clearance, too tight fit/loose fit, races/rolling elements were not aligned. And, I am trying to figure out how best I could tell the mechanical people about mounting issue. It seems like a taboo to highlight any installation issue here!! Appreciate any advise!

Thanks for the reply "Sine wave".

Can you post a picture of the outer side surface ( the side with the thread)?

Can you measure the total length of the sleeve?

Am I seeing this wrong or does this expand section of your picture of the sleeve show a number of N303 (see he attached close-up from your picture) or does N303 have a different meaning of this sleeve?

Thanks and Have a Great Day,

Ralph

Hi Ralph, this is SKF H311 adapter sleeve and what you are seeing as N303 upside down is in fact SWEDEN😃

I will try to post the picture with the thread side tomorrow. But attaching few pic if that is helpful

@Registered Member posted:

Hi Ralph, this is SKF H311 adapter sleeve and what you are seeing as N303 upside down is in fact SWEDEN😃

Now, that is funny !!!!!

These pictures shine a little more light on the situation.

The sleeve appears to be completely through the bearing in the picture taken, either before the complete removal or complete installation, which ever the case may be. Unless..... the sleeve has been pulled so tight with the nut that the"big" end has pulled to deep into the bearing.

Looks as though they were removing the old bearings, base on the "Brown smear" on the DE of the shaft where there is no bearing in the picture.

Do they measure the clearance of the bearing with the bearing standing upright on a flat surface before installing the bearing, tapered sleeve and the nut on the shaft and then tighten the nut to obtain the correct installed clearance?

Question: Is the brown mark on the inside of the bearing's inner race ring rust or brown grease?

The markings, to me, now may appear to be associated with maybe "grease" since there appears to be brown colored grease used in the bearing, possibly on installation, and seemingly also with a "clear" grease used. What type grease does the bearing manufacturer recommend?

Thanks and Have a Great Day,

Ralph

@Ralph Stewart, the pictures I believe were taken during removal and the dark brown mark has to be the rust as you can see in this attached! The grease used which you referring as clear looking may be sort of cream colour, unsure about the type.

Assume the check the initial and final clearance during installation but the condition is telling probably otherwise. I am trying to understand what is going on here repeatedly.

Wrong inner race taper lock, it is not long enough to fully engage the bearing inner race is my bet. The rust on the shaft where bearing resides is due to loose fit of taper lock inner race sleeve. The inside of the sleeve shows minimal contact, the rusty areas are not making full contact, shiny areas are in full contact. The use of a micrometer on the shaft will most likely show shaft is undersized and not round. Not necessarily the cause of your initial question of the marks in bearing outer race.

The fan base appears to be machined flat, I know the bearing feet are machined flat, but yet the shim under the bearing is not truly a real shim....the shim under the bearing needs to be as flat as the fan base and bottom of the bearing block, period. There is also indication the shim is not making full contact with underside of bearing block.

As for your original posting, it appears installation of the bearing is an issue...NEVER use a metal/steel hammer to lock the nut, a spanner wrench is the proper tool to set bearing clearances. I would contact your bearing supplier and have them get involved to get to the bottom of the bearing parts being correct and proper installation techniques.

Dave

  Never is a long long long time. Spanner wrenches will work on smaller bearings but they are for the most part useless for larger bearings. It is very difficult if not impossible to reduce the unmounted clearance by 1/2 without using mentioned tools.

Yes, never is a long time, it is a mental decision to use correct tools and methods no matter the task at hand. Steel on steel with a hammer will create dents in bearing races. Free advice, put spanner wrench on bearing nut, use fan wheel as your wrench or driven shaft, don't impact the bearing. Use dead blow/soft mallet if you must bang on the nut.

https://www.youtube.com/watch?v=8W3BQ6vc5t8

Example of how not to install fan bearing on 5 7/16" shaft, bearing seized up with in 10 minutes of run time

Dave

  You should support the shaft to prevent bearing damage.

Dave just how does this endorse you ideas about installing these bearings.

Thanks for your valuable advise. Have been trying to highlight the issues, unfortunately couldn't convey the message as the mechanical team wouldn't accept the fact that it could be wrong sleeve or installation issue!