Bearing Failure in Motor-Driven Shaft with 40 kW Load

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Discussion Overview

The discussion revolves around the issue of bearing failure in a motor-driven shaft system that operates under a load of approximately 40 kW. Participants explore potential causes of failure, including bearing selection, alignment, and load conditions.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant describes the setup involving a motor, shaft, and specific bearings, noting that failures occur within 2 to 3 months of operation.
  • Another participant suggests that if the load specifications are not exceeded, axial load on the self-aligning bearing may be an issue, recommending a switch to tapered bearings.
  • A different participant advises consulting a SKF dealer for bearing failure analysis, indicating that various factors such as belt tension, overhang, or improper gearbox design could contribute to the problem.
  • One participant raises the possibility of alignment issues at the load end causing excessive load on the bearing, and mentions the potential impact of imbalance, while noting the difficulty of diagnosing the issue without visual inspection of the setup.
  • A request is made for a sectional view of the bearing arrangement to facilitate further analysis.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the causes of bearing failure, and the discussion remains unresolved with no consensus on the specific issue or solution.

Contextual Notes

Limitations include the lack of detailed visual information about the bearing arrangement and the setup, as well as the absence of specific data on operating conditions and alignment measurements.

Koenigindia
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I have a problem of bearing failure. A motor drives a shaft thro a flat belt. This shaft is connected to a load of around 40 kw. The shaft has 1309 self aligning ball bearing as floating bearing at the back end of shaft. On the load side there is a bearing 2209 NUP. The bearing inners are locked by circlips and outer is locked with housing. But within 2 to 3 months of continuous running, either the shaft shifts away from the load after abrading the circlip or the bearing 2209NUP fails. Will somebody be able to throw some light on what is wrong around here.
 
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My recommendation would be to take or send the bearing and gearbox (or pictures) to a SKF dealer. The have people that do bearing failure analysis on bearings many times a day, and there is likely very little they have not seen.

It could be as simple as your belt being too tight, too much overhang or to the wrong bearing being used, all the way to improper design of gearbox.

SKF sells a failure analysis book for $5 plus other info here:
http://www.skf.com/portal/skf/home/aptitudexchange?contentId=0.237932.237933.237935.237962.238715
 
Do you have any kind of vibration monitoring on this set up? It sounds to me like your alignment at the load end may be off putting much more load on the bearing than should be. There is also the issue of imbalance that could be playing a part as well. I can keep guessing, but its a lost cause.

It is impossible to tell you exactly without being able to see the entire set up and what the bearing looks like after failure. Is there any discoloration on the bearing?
 
can u attach the sectional view of the bearing arrangement, so that i can analyse the bearing arrangement..
 

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