CEPSTRUM ANALYSIS PREDICTS GEARBOX FAILURE

A one-step gearbox was run under controlled laboratory conditions until failure occurred during continuous operation with an overload of about 50 percent. The gearbox ran for a total of 497 hours, until three teeth of the input gear broke at the base as a result of fatigue. Gearbox vibrations and temperatures were measured during operation. The following analyses of vibration signals were used for condition monitoring: spectrum analysis; cepstrum analysis; acoustic emission; and statistical analysis. The imminent failure could be predicted only marginally on the basis of spectrum analysis, but more accurately on the basis of cepstrum analysis. Under normal load conditions, a failure of this type might be predicted by cepstrum analysis several days in advance.