Rolling element bearings are mechanical elements present in most rotating machines. Their useful life depends on a series of factors such as: load, running speed, lubrication, assembly, temperature, external forces caused by misalignment, unbalance, etc., and therefore it is practically impossible to determine their useful life by analytical methods. The importance and criticality of these components makes it necessary to use modern techniques of predictive maintenance (based on the vibration analysis) that contribute to a better recognition of their condition and, therefore, the availability of the rotating machines in which they are installed.

The objectives proposed in this chapter are two: to identify the defects in rolling element bearings through the spectrum and waveform based diagnosis; and to determine the factors to be taken into account to predict the degree of deterioration or bearing damage severity, in order to estimate its remaining useful life. It is of key importance to take into account that the vibration spectral analysis, on top of indicating at all times the bearing condition, will be an essential tool to determine the root cause of chronic bearing failures to be able to definitively eradicate them.