Now this is a tricky question to answer… We have a few
contenders: high frequency vibration analysis, regular vibration analysis,
ultrasound, oil analysis, wear particle analysis, and infrared analysis. Let's
start by ruling a few of them out.
Infrared analysis is used to detect heat in a bearing, which
is a late stage fault condition, so that's not your best option. Regular oil
analysis can detect the presence of the wear metals within the bearing,
but wear particle analysis is a better tool for that. Regular vibration
analysis (i.e. velocity spectra) provide very clear indications of bearing
faults, however the high-frequency detection techniques provide an earlier
warning. That leaves high-frequency vibration analysis, ultrasound, and wear
particle analysis.
Ultrasound is easiest to use. Push the probe against the
bearing and listen carefully and you will hear if the bearing is in distress.
(You can also record and analyze a waveform, but now you may as well be
performing vibration analysis). Many would argue that high-frequency vibration
analysis (such as enveloping, PeakVue, shock pulse, and others) provide a
clearer indication of the nature and the severity of the fault. But it does
require more training and potentially a more expensive system to perform the
collection and analysis.
And that leaves wear particle analysis. Let's just say that
if you own critical gearboxes, you absolutely must perform wear particle
analysis. Performed correctly, you will detect the first signs of wear, and
complex gearboxes provide a greater challenge for the vibration analyst and the
ultrasound tools.
Although I haven't really answered the question, I am hoping
to have put you in a position to make the right decision for your situation.
This tip is provided by Jason Tranter, Managing Director of Mobius Institute.
For more condition monitoring tips, continue to visit the IMVAC – International Machine Vibration Analysis Conference –
blog every week. To learn more about IMVAC and the event nearest to you, visit
vibrationconference.com.