Diagnosis of bearings condition - non synchronous peaks in FFT
Mariusz Rosenkranc
?Team leader ?Project Manager ?Quality Manager ?Direction of operation ?V-ice president Info Marine Service ?Vibration Analyst Cat 3 ?Condition Monitoring Engineer
Realy only on bearing defect frequency is a mistake that can lead to failure in indicating condition of bearings.
Described in this case el. motor has revolution speed 1770 and bearings 6308 with folowing bearings frequency:
The el. motor and screw pump is positioned vertical.
During analysis it was indicated high bearing envelope.
There weren't any bearing frequency seen on FFT velocity or envelope:
It was decided to replace both bearings.
Next measurements and feedback from Crew confirm ours diagnosis.s.
Conclusion:
It is imporant to known that not always bearing defect frequency are visibile when bearing has defects. If we have only number of the bearing and don’t have exactly producer then the bearing defect frequency can be diffrent that we assume. Bearing with significant defect during its last worn down stage may have only rise floor and haystack shown in velocity/envelope.
S.r Engineer at MVS ACMEI technologies Pvt Pvt Ltd
2 年Yes I faced one pump in my plant vibration are with in trend no fault frequency is there in spectrum also, but pump bearing cage was broken but we identified problem by checking lube oil sample ferrous content.......