MEMS versus
Piezo Accelerometers

This paper demonstrates the importance of maintaining a sufficiently high sample rate for the early detection of bearing failures and other failure modes often identified by envelope analysis. 

The study uses data recorded at high sampling rates, then downsamples to lower rates, more typical of those associated with MEMS transducers. 

The analysis procedures are then applied, and the trend development of selected findings are shown to illustrate the principle. 

It is shown that envelope analysis requires sampling rates high enough to capture the signature of regular impacts well above the normal running speed of the machine, preferably within the multi-kHz natural frequency range of the component and housing.

David Futter, Department Leader, Condition Monitoring Consultancy, Bachmann Monitoring GmbH