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Example.
We are going to show the analysis procedure on a signal obtained on a seating of an inlet
transmission shaft with the speed frequency 25 Hz (1500 rpm) and with a gear with 65 teeth. So called
tooth frequency can be obtained by simple multiplication of the shaft revolution frequency (in Hz) by
the number of teeth.
f
GMF =
f
gear mesh frequency
GMF
f
speed frequency
speed
z
number of teeth
In our example the tooth frequency is 1625 Hz (so approx. 1,6 kHz).
What are the possibilities?
Condition 1:
The transmission is OK and tooth frequency of 1,6 kHz slightly increases vibrations in the first two
frequency ranges.
Condition 2:
Vibrations are concentrated in the last frequency range 5 – 16 kHz, the vibrations in the last area are
the same as in the area, where the tooth frequency shows itself - bearing failure
f
z
speed *
37
Adash 4900 – Vibrio III
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