April - Library

AMMJ Lessons Learnt In 45 Years of Condition Monitoring 25
In the meantime
It took some months to write specs, call for bids and then analyse them and place orders. In my absence, the
Yallourn (old station) people had bought a replacement balancing instrument. It had a significant advance on
the old ones – it had a frequency scale! Without them realising this capability, we had a way of finding vibration
signatures (spectra). Several intractable vibration problems were solved. (Beebe, 2001)
I recall the stores manager raising his eyebrows when asked to locate a large mill bearing and count the number
of rollers in it!
Lesson # 11 Check your cupboards – you may have under-utilised equipment with as yet
unknown capability! See again Lesson #3.
Putting the advanced vibration analysis equipment to work
No single supplier could provide all the items we needed (this was in 1975). Connection of vibration transducer
to signal conditioning to analyser to plotter was easy to get a one-off vibration signature. But as our aim was to
start routine signature analysis, repeatability was essential. After some experimenting with signal outputs, gain
and attenuation, this was achieved.
The operating instructions were apparently written by the electronics design engineers and were difficult to
understand by we mechanical types! I wrote a handbook of simple step-by-step instructions for applying all
the equipment. An example is shown in Figure 4 of the RTA front panel showing the required buttons and dial
settings.
Figure 4 Front panel of the analyser showing how to set it up (from the operating handbook we wrote).
We designed a special graph paper so that plots could be compared by holding sheets up to the light. Our intent
was to eventually have this comparison done by a computer, but in the pre-PC days….
As the equipment was to be shared around five power stations, we set up clearly labelled carry cases to facilitate
collection by any driver. Each case had the required connecting cables. Unfortunately, after some time cables got
lost. Locating the cases also took time.
In the ensuring years, more advanced FFT analysers, multi-channel tape recorders, later versions of other
instruments were obtained. A major re-organisation set up a central specialist group.
Lesson #12 Specialist test equipment needs to have a regular owner and full-time skilled
operator
Hand-portable analyser/collectors and associated computer packages have become commonplace, so our dream
was realised.
Vol 24 No 2