Analysis is
performed by asking one seemingly simple question:
-
"Are any of the
amplitude values higher than desired ?"
-
If the answer
is "No", move on. Remember, this includes all areas of the spectrum
from 1x rpm thrugh harmonics out to high frequency, bearing related frequencies
while keeping in mind the amplitudes in these ranges should be judged by
different standards. For instance, you should become alarmed at much lower
amplitudes when analyzing bearing-related vibrations than when analyzing
1x rpm amplitudes.
|
Sample
Spectrum: Q1 - Are Any Amplitude Values Higher Than Desired ?
-
If, however, the
answer is "Yes", you must move on to a second question:
|
-
"Where are they
coming from ?" More technically, what is the source of the "excessive"
amplitudes that you are concerned with ?
-
The source of
the vibration is judged by the frequency(s) of the amplitude
peak(s) being examined. Spectrum resolution must be kept in mind during
this process. The better the resolution, the better your judgment.
|
| Since the
frequencies displayed actually cover frequency ranges, the
best judgment of frequency you can ever make from a spectrum is
an estimate. |
| Spectrum resolution
goes to the heart of a very important question - how accurate is the data
(frequencies) you are using for your analysis ? Without fully understanding
the implications spectrum resolution has for the data you are analyzing,
you will never be a good analyst. |
