This case is presenting a defect of a Triple Ring Bearing at the 2nd Press CC Roll. CC refers to “Controlled Crown”. This has the ability to crown or bend the roll slightly to conform to the nip that is pressing against the other roll.
This bearing is very expensive around 50K USD and is very large. It is called a triple ring bearing as it has two sets of rollers so there is an “outer race of the outer bearing” and there is an “inner race of the outer bearing” then there is an “outer race of the inner bearing” and then finally there is an “inner race of the inner bearing”.
In the trend view you can see that confidence was very low at about 20% and showing just a few harmonics of outer race defect. As the defect got worse the confidence climbs to 100% as there are harmonics in all bands. They watched this bearing for a little over a year, but this is not normally the trend on these Triple ring or race bearings. Normally when these are discovered you have about one month at the longest and could fail within a few weeks. These defects are of very high priority.