We just experienced as failure on one of our reducer. It is a Philadelphie Gear reudcer for a MPS89 type mill.

The bottom bearing failed and we did not catch the failure with our Oil Analysis program. Can we effectively use ultrasound reading to trend specific reducer bearing in a large unit ?

The bearing i am looking ot keep track of is a low speed (about 100 rpm) and is located in an oil bath situated in the bottom of the reducer. It is about 16" diamter OD and the bearing housing is attach to the reducer housing which we could use our contact probe against the housing wall...

If anybody has success stories on reducer using this technologies, i will like ot hear some specific examples....

Thanks

Seabass

Have you concluded that oil analysis cannot detect this slow speed bearing failure?

What kind of oil tests do you do? Any wear analysis done?

I'm not familiar with coal pulverizer so what type of bearing is it, rolling element or sleeve bearing?

What is the bearing spec?

Seabass,

Yes, ultrasound can be used provided that you can get a good measurement point close to or directly on bearing housing. I recommend one measurement point per bearing and one per gear stage. Mark each point for consistent measurements. Log the ultrasound level (dB), level variation, and audio characteristics at each measurement point.

Vibration measurements can also be effective, especially the high frequency acceleration level, waveform, and spectrum and the demodulated spectrum. It is unwise to rely solely on a single technology like oil analysis for monitoring the condition of a large gearbox.

Walt
w_f_strong [at] msn [dot] com