Monoblock shaft heat failure 1

[MERO DZ]

Please can some one help me about my fan shaft mono block failure heating.
see attached report for more information!!!!!

 

[romke]

it looks that for some reason or another the bearings overheated quite a bit with subsequent failure. it is indeed remarkable that both failed at the same time - the only thing they have in common is the grease. is there anything known about the amount of grease in the bearing and whether they have recently been greased or has grease been recently added? more bearings fail due to excessive grease then due to little grease. has anything changed in the maintenance carried out, handling of the maintenance by other personnel etc?

 

[Strong]

Was any balancing weights recently installed by welding without a proper rotor/wheel ground?

Walt

 

[chicopee]

Are the bearings under reverse bending when the fans are in operation? Any known undue vibration? Do both fans have the same hours of service? Were the bearings replaced in the recent past?

 

[chicopee]

One more thing what are the fans exhausting, another word any contaminants in the exhausted fluid, ie, other than contaminated air.

 

[Tmoose]

belt drive ? Any recent changes in shaft speed, belt replacement, or even just belt replacement?

What is the function of the hex plug at the top of the housing?

Service history? Including bearing replacement, relubrication, or anything else.

The bearing housings appear to have been around for a few years, based on paint condition.

Please provide pictures of the condition of the other bearing in each mono block housing

 

[MERO DZ]

Find monoblock shaft arrangment

 

[MERO DZ]

please see the attached, is that right????

 

[TimSchrader2]

Hello
Different materials and differenetial expansion, linear or radial? The roller bearings can handle this better then the balls.

 

[Tmoose]

The ball bearing looks quite dry, which might // just // be the result of becoming so hot.
How greasy are the tapered roller and cylindrical roller bearings ?
** Certainly confirm the ball bearing is actually being greased.
Was the bearing greased manually before installation, or installed right out of the package, then greased via the shared lubrication port.

What is the environment of the fan ?
If the upper most seal is inadequate by design or after a repair then the upper bearing would be subject to contamination first.
I think there is a flinger or slinger missing above the ball bearing.
(I just saw in the second posted image the upper cover has a V-ring bearing on it, and what looks like a gap between the bolted cover and bearing

As suggested by others, if the ball bearing and the tapered roller bearing get into a thrust fight, the ball bearing will lose. I suspect the if the inner races are clamped by the shaft nut as shown, the cover etc above the ball bearing is supposed to have a gap between it and the outer race. If parts were left out or improperly installed