Modeling of low shaft speed bearing faults for condition monitoring

A general model of faulty rolling element bearing vibration signals is established. The efficacy of the envelope-autocorrelation technique for condition monitoring of such bearings leads us to derive the envelope-autocorrelation function of the model in the case of very low shaft speed. For application to the bearing condition monitoring, a simplified model is given. Finally the comparison of simulated data using the model with in situ data confirms the satisfactory performance of the model and the effectiveness of envelope-autocorrelation as a fault detection technique for low shaft speed bearings. (C) 1998 Academic Press Limited.