Early detection of bearings problems by use of ultrasonic detectors is claimed by so many manufacturers. Some claim to detect it around 40KHz range , others say above 100KHz range and so on. What is sufficint ultrasonic frequency range for early detection of bearing problems so that we can take preemptive measures to avoid bearing problem. By the time, we can detect it through vibration analysis, the bearing is almost gone and can't be survived except lingering the doom. any suggestions, agreements, or disagreements?
Regards.

"By the time, we can detect it through vibration analysis, the bearing is almost gone and can't be survived except lingering the doom. any suggestions, agreements, or disagreements?"

If that is the case, I would suspect that something is not correct in your vibration analysis set-up.

My view of this as a consultant carrying around a system that collected at some 340kHz I never was present when the damage was so new, maybe on a on-line you may see it. Next problem is that as the damage get older that hi freq is lost and pop up in "normal" demod ranges up to 12-20kHz passing the magic SPM freq of 32kHz on the way. So even using 2 systems having HP filter of 600Hz and 2kHz you sometimes see a difference. New(er) damage, you get hi leve at 2kHz-12kHz when getting "older" it goes down and the 600-12kHz range go up more, for a "middle" age you get about equal relative levels from both. Just as examples. When all is said and done, pending speed etc. ISO level at 10-1000Hz go up and then as you say your time before self shut down may be short. Normally there is a fair time period during this destructive cycle to both detect, predict and sometimes remedy or at least plan repair. I have a friend in India that can help you see the light. Email me and I can email his info. Olov

quote:

Originally posted by Danny Harvey:
"By the time, we can detect it through vibration analysis, the bearing is almost gone and can't be survived except lingering the doom. any suggestions, agreements, or disagreements?"

If that is the case, I would suspect that something is not correct in your vibration analysis set-up.

Danny,
What I mean by vibration analysis is normal spectrum analysis, excluding demodulation , peak vue or ultrasonic diagnostics. By the time, antifriction bearing vibration is reflected in
spectrum or overall readings , the bearing can't be revived. It is only a matter of time, when to replace. I think, ultrasonic can diagnose bearings probelm in the
most incipient stage but what frequency range of ultrasound to use? That is my question.
Regards.

Kind of like the second law of thermodynamics states - things get worse with time.

When the bearing flaw is detected, it is not going to get better. You can add lube if needed to correct a situation, but the bearing is not going to be in better condition.

As suggested, your data analyses system is flawed if it isn't doing the job. It's kind of like you're saying a sub-system with less capabilities is better than the full-blown diagnostic system will full capabilities.

You can't revive a bearing; only track it to failure. But utilizing proper maintenance practices, alignment, balancing, lubrication, etc.... you can get the most out of the bearing's expected life. No diagnostic tool will take the place of PM and proper maintenance practices. Or so I think.

Akhtar,

Ultrasonics is a good way to detect the high frequency, random vibrations associated with lubrication problems, and if applied properly in conjunction with your lubrication program, can slow the inevitable progression to failure that Sam is talking about. I am limited in my experience in ultrasonics, but have used it to monitor bearings while lubricating them. It is one of the best ways to ensure the proper amount of lubricant is applied, imo.

Someone may correct me here, but I think that ultrasonic technology is a little more user-friendly that vibration analysis, too.

So is the yellow handle analyser that I frequently use also, problem is the calibration and trending facilities.... Olov