I think three factors to consider will be
1 – Max temp of the oil film. As oil film temperature goes up, viscosity goes down and oil film thickness goes down which may result in wipe. A 20C change in oil film results in approx halving of operating viscosity for VI=95%. Not as much of a change for higher VI oils including many synthetic oils.
2 – Max temp of babbit – often given as 140C.
3 – Babbit mechanical damage (fatigue or plastic deformation) where damage threshhold load may decrease as temperature increases. I saw a lecture from Kingsbury, and they had a curve of bearing temperature limit vs loadingg (pressure). It is flat (140C max operating limit, 120C recommended limit) up until 800 psi. Then it starts decreasing at 10C per 100 psi. When I asked the presenter about it, he was adamant this was not an oil film thickness issue... it was babbit mechanical damage with threshhold affected by temperature.
A few other tidbits:
Babbit melt temperatures ASTM grades 1,2,3,5, 7. The lowset is 180C.
There are also a variety of locations to monitor bearings and if the hottest is not selected, the alarms/trips need to be more conservative. For center-pivot tilting pad, the hottest spot is about half way from center to trailing endge. For offset tilting pad, it can be almost at trailing edge. For tilting pad, it is often 75/75 location.
Another excerpt from Kingsbury presentation:
•Typical sliding bearing rating limits:
–500 psi unit loading
–.001” minimum film thickness
–240 F maximum film temperature
Note on the link below they show item #1 above more likely to be limiting at low speed, item 2/3 at higher load:
So I think you can see that there are a lot of factors to consider.
Why are people trying to turn this thread into an insult forum?
By no means do I want to create any negative feelings. But I think the tone you have conveyed in earlier posts and continuing to the latest post is slightly ungrateful. People give you suggestions and you responded "what kind of engineer would set vibration and temperature limits for a 10 million dollar piece of equipment based on what someone told him on the internet?" OK, that's a fair enough comment, and in the full spirit of your comment, people suggested you contact the OEM (after all we don't know you or your equipment). In response to that suggestion you had another snappy comeback "Have you ever called GE and asked for information? I would guess not."
Everyone here is just trying to help. Any negative tone in this thread was originated with you imo
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