Investigations employing the high-frequency resonance technique (HFRT), which diagnoses defect frequencies of rolling-element bearings of different makes, have been carried out. Raw vibration signatures of bearings at different speeds of operation have been demodulated, and envelope-detected spectra analysed to evaluate various defect frequencies and their energy levels. A relative comparison of various bearings has been made on the basis of identified defect frequencies and severity of defects. These frequency values and their energy levels are used to monitor the intrinsic conditions of bearings as well as to establish the severity of existing or developing defects in the bearings.
The investigation gives a realistic approach to monitor the intrinsic condition of a bearing. It can be successfully utilized to select appropriate bearings and for performance evaluation, and can act as a reliable tool to establish a safe bearing operational limit. Investigations can serve as a precise quality control instrument for the earliest detection of defects of even the smallest nature, and can be used as an 'on-line' bearing condition monitor, if required.
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