Condition monitoring of very slowly rotating machinery using AE techniques

In industry it is often very slowly rotating machinery which is the most critical to the production process as well as being the largest and the highest value. These factors combine to increase the economic requirement for Condition Based Maintenance and hence the importance of suitable means of Condition Monitoring. However slow rotational speeds result in reduced energy loss rates from damage related processes and because of this Condition Monitoring techniques which detect energy loss tend to be more difficult if not impossible to apply. Perhaps surprisingly this is not the case for the Acoustic Emission (AE) technique which is well suited to detecting very small energy release rates. As a result AE is able to detect subtle defect related activity from machinery, even when it is rotating very slowly. In this paper a new AE based signal processing approach is introduced which can provide simple but sensitive means of detecting the presence and evolution of faults in very slowly rotating machinery. These developments have further led to the creation of what is believed to be the first easily retro-fitted and affordable on-line monitoring module for very slowly rotating machinery.