Ultrasound inspection of motor bearings and gearboxes is a proven non-destructive method for condition based monitoring. Using the UL101 together with software for comparative and baseline analysis has immediate impact to the bottom line through cost avoidance.
There is no single ultrasound characteristic that will, when considered alone, help determine the condition of a component under test. Digital indicators of relative measurements such as decibels or root mean squared (RMS) should not be solely used for trending. A significant change in average amplitude is just one indication of a problem. However, change in amplitude can also indicate change in speed and load.
Another factor to consider when monitoring bearings is the quick spikes in a signal, called EPS by CTRL. These events are loud impacts relative to the average amplitude that indicate excessive wear. Further, these events occur much earlier in the ultrasound frequency range than indicated by vibration or heat.
Monitoring a bearing routinely for both average amplitude and events is a good practice for establishing what a good bearing should "sound like." Changes to the characteristic sound indicate changes to the condition of the component under test. Addressing the potential problems early will avert catastrophic failure, save production downtime, parts swapping, and man-hours.