Acoustic emission is one of the effective techniques used for the condition monitoring of rolling element bearings. Contamination is one of the major reasons for bearing early failure due to presence of solid particle in lubricant grease. In most cases, outer race is stationary and the inner race is attached to the rotating assembly. The lubrication is very essential for the bearing to perform under various demanding conditions. The main aim of this project is to analyze the effect of contamination of lubricant by solid particles on the dynamic behavior of rolling bearing. Green sand at three concentration levels 5%, 15%, 25% and different particle sizes 75 μm, 106 μm and 150μm is used to contaminate the lubricant. Experimental tests have been performed for different load and speed condition in good and contaminated ball bearings lubricated with grease. The trends in the amount of AE waves affected by the contamination of the grease were determined. Acoustic emission signals were analyzed in terms of RMS, kurtosis, and peak-peak.
Rotating machines with center-hung dynamic balancing rotors are widely used in several industries. During operation, the rotor may gain or lose material due to the wear and deposition of foreign materials in the rotors. As a result of this, the rotor becomes unbalanced. Unbalanced rotor usually causes excessive machine vibration that generates large forces on the bearing. It also results in enormous power loss and leads to potential damage to the system. So, the vibrations caused by the rotor have to be continuously monitored to prevent the potential damage to the rotating machinery. In this project, experimental studies are performed on a dynamic rotor test apparatus to obtain the vibration response of the rolling element bearings in the rotating system under several masses with different running speed conditions. The shaft is attached with four rotors, each having different mass and rotating in different planes. The rotor shaft vibration responses on the bearings are obtained using piezoelectric accelerometer. Dual-channel vibration analyzer (ADASH) is used to analyze the obtained vibration data. The identification of system characteristics is to be carried out. The results thus obtained can be used for condition monitoring of the unbalanced rotor system.
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