Effects of Rotating Shaft Misalignment on Bearing Life and Lubricant Failure

摘要

This study looks at plant and machinery at West African Mills Company Limited (WAMCO), with the view to identify sections within the factories with high cost of maintenance and provide a solution to reduce operating costs. Records of breakdowns at various sections of the plant were analysed and the first stage milling section at WAMCO II was found to have the highest cost of maintenance. On average, the breakdown of each of the three SCS4 grinding mills is about 14 times in a year. Furthermore, 27 bearings and 1.625 buckets of grease are used on the grinding mills alone costing an average of C10,000.00 annually on their maintenance. Some experiments were performed to ascertain how the rotating shaft misalignment occurs and the consequent change in parameters such as temperature, viscosity, power, and vibration. Bearing temperature readings at various misaligned shaft positions gave some indication of the criticality and likelihood of machine breakdowns. It was observed from the correlation analysis that there exist a strong positive relationship between the number of bearings, bucket of grease and man-hours used during breakdown and repairs. It was recommended that modern devices for monitoring be acquired and proper condition monitoring of the plant made to minimize the plant breakdowns and save money. Also, proper selection of bearing type for the mills should be looked at.