现行大型电机的监控与管理之一.ppt

* * Bearing life Bearing life is normally given as the L10 life, i. e. the time during which 10% of the bearings will fail although they are correctly lubricated. Statistically, a bearing can be expected to reach five times its rated bearing life. Manufacturers like SKF say that the design life is infinite, as far as steel quality is concerned, but only under the condition that the bearing is properly loaded and lubricated. Using LR/HR measurements and the possibilities offered by LUBMASTER for finding the optimal lubricant, one can make the best use of this potential bearing life and safe the cost of new bearings, replacement work and downtime. * 维修策略的发展现状——离80%实现RCM还相去甚远。 * Maintenance - three alternatives There are three basic maintenance philosophies: Corrective maintenance: wait for the breakdown, then repair. This method is suitable for easily replaced part whose failure will cause little inconvenience. Used for important machinery, it implies a large risk for downtime during required time, for administrative and technical delay, and for secondary failures. Direct preventive maintenance: This is planned maintenance at defined intervals, e.g. lubrication, cleaning, bearing replacements. The method disregards the actual operating condition of the part or machine. It is inefficient for unpredictable components like bearings (waste of potential life, risk for installation faults, no real security). Predictive (preventive) maintenance: Maintenance is condition based, which means that repairs or replacements are made only when a significant deterioration in machine condition is detected, and largely during ”nonrequired time”. Detecting beginning faults in time for planned repairs requires condition monitoring. Correctly used, the method reduces unplanned stops, secondary failures, undetected failure time, administrative and technical delay, and spare part stock. Improvement maintenance: Machines are regularly modified to avoid failures that have occurred in t