A bearing defect does not always appear clearly in overall vibration levels.
During routine vibration measurements on a fresh water ejector pump electric motor, our analysts identified an increase in the bearing envelope values.
The overall vibration level alone did not indicate a critical condition.
The key information came from the FFT envelope spectrum.
📊 A clear BSF (Ball Spin Frequency) and its harmonics were detected, a characteristic indication of developing rolling-element bearing damage.
Follow-up measurements showed that the condition was progressing, confirming that the bearing required attention.
Based on the analysis, we recommended:
🔧 Bearing replacement
🔧 Follow-up vibration measurement after maintenance
The bearing was subsequently replaced, and inspection confirmed damage to the rolling element.
After maintenance, the vibration measurements returned to normal characteristics and the bearing-related frequency components were no longer present.
✅ Result: The developing bearing defect was identified and addressed before it could lead to a more serious failure.
This case shows why condition monitoring is about more than checking overall vibration levels.
Advanced analysis techniques such as enveloping and FFT spectrum analysis can reveal developing bearing faults at an early stage, when maintenance can still be planned rather than performed in response to a failure.