Investigations of Antifriction bearing defects using Vibration Signatures

Antifriction bearing failure is a major factor in the failure of rotating machinery. As a fatal defect is detected, it is common to shut down the machinery as soon as possible to avoid catastrophic damages. Performing such action typically results in substantial time and economic losses. Therefore it is important to monitor the conditions of antifriction bearings and to know the details of the severity of defects before they cause serious catastrophic consequences. The vibration monitoring technique is the most suitable method to analyze various defects in bearing. This technique can provide early information about progressing malfunctions. Time-domain analysis and frequency domain analysis have been employed to identify different defects in bearing running at three different speeds. Defect-free and defective bearing are used for testing. Time-domain and frequency-domain signals acquired for both good and defective bearings Time waveform indicated the severity of vibration in defective bearings. The frequency spectrum is used to identify the amplitudes corresponding to fault frequencies and enables to predict of the defect presence. The roller bearing is considered for analysis. Three types of defects namely outer race, inner race, and rolling element defect are considered. Experimental data of both defect-free and defective bearings are processed to show the effectiveness of the fault diagnosis using this method. In fault monitoring and diagnostics of bearings, real-time processing and fast on line fault indication are becoming increasingly important. Towards this goal, attention has focused on a search for the use of effective signal processing and signatures extracting methods to realize immediate fault detection.