Vibration data from the Alert generated on March 4, 2023, shows the initiation of the defect, shown in the green box below. The vibration anomaly increased the amplitude on one of the vibration probes. For this machine, amplitudes below 6 Mils (0.006 inches displacement, peak-to-peak) are considered good. The Acceptable amplitude region is from 6 to 10 Mils, and High is from 10-20 Mils. In this instance, the levels increased to 7 Mils, which is still in the acceptable region, but there was a definite increase in vibration values over the 6 weeks shown in the first graph. The lower graphs are plotted with the Load parameter included for the defective unit on the left and the other (good) unit on the lower right. We expect the vibration amplitudes to track each other from the two sensors on each machine. Measuring vibration amplitudes using similar loading conditions is an excellent way to increase analysis accuracy. The Health Score for this generator also deteriorated by about 10%, showing the direct correlation between anomaly detection and health scores. The unit was repaired and put back in service.
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