Based on this study and analysis, the following major conclusions are drawn:8,9
Data brought out in this study can be used for appropriate bearing selection, performance evaluation and other relative comparisons for NU 330 bearings.
From the results of various bearings by high-frequency resonance technique (HFRT), it is recommended that bearing 'B' (new) is not used since the performance of this bearing is much inferior to that of bearing 'A' (new). This is also confirmed by the field data, which indicate that the failure rate is as high as 25% for the bearing 'B' (new) as against 0.9% for the bearing 'A' (new).
Energy levels of defect frequencies detected by HFRT for bearing 'A' (new) at the maximum speed of operation are, in general, less than 300. This may be taken as guide to study for establishing the severity of defects for bearings under test and also as the limit of trouble-free normal and healthy bearing operation.
Continuous indication of energy levels of more than 300 for any defect frequency should be taken as serious and the concerned bearing may be treated as defective with incipient damage.
Any bearing showing energy levels of more than 500 for any defect frequency should not be used to avoid catastrophic bearing seizure/failure.
Vibration pick-up mounted on the bearing outer race avoids the effect of passage on the finally received signal. It is the best indication of bearing health, compared with the other pick-ups.
To avoid a catastrophic bearing seizure,...
TABLE OF CONTENTS 
