I am working with a public dataset (mentioned in few papers) of vibration measurements of broken and healthy gearbox under various load. Most of the measured channels posses the same parameters no matter whether the gearbox is broken or not - almost same FFT, same histogram of the raw data, same cepstrum, same IMF (obtained by EMD).
However one channel carry a significant difference in vibrations from the broken and the healthy gearbox (see picture). I checked some papers and books about this topic (fault detection in gearboxes, FFT analysis of gearboxes etc.), but they seems to represent way to nice and clean results far from the dataset observations I have. So I am still quite unable to understand why the FFTs looks different in this way. Few notes about the dataset:
- frequency of measurement / or speed and size of gears are unknown (I guess something for the FFT x axis - it has no real meaning)
- the broken gearbox suppose to suffer with a "broken tooth"
Can you form any hypothesis, why the frequency spectrum is changed in the way displayed in Figure in relation to "broken tooth" fault?