Bearing Spall Length Estimation Using Tach from Vibration Processing

Vibration analysis has long been used for bearing fault diagnostics. Envelope analysis or some other cyclo-stationary process have been used to define a fault feature or condition indicator that is correlated to the spall length. However, no study has defined a process for estimating spall length on real-world data. The problem is that the spall length is a time-domain property of the signal. In this paper, a synthetic tachometer signal is generated from the fault itself. It is synchronous to the rolling element entry into the spall, allowing for a time-domain representation of waveform using the time synchronous average. From this, an estimate of the length of the bearing fault can be determined.