預知保養系統中預警值設定之探討

• Main Author: 江世章
• Other Authors: 馬志高
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/62530217032747026982

碩士 === 中正理工學院 === 兵器系統工程研究所 === 85 === In recent years, the rising cost of machine maintenance has driven engineers to develop more economical and efficient method to determine machine health and to plan accordingly the required preventive and corrective maintenance. The most popular technique in use today is a predictive maintenance program based on condition monitoring. Predictive Maintenance systems which use personal computers, handheld data collectors and sophisticated software can be powerful tools for the maintenance department. Computers can greatly automate this review and evaluation process; however, system automation will only be effective when meaningful alarm levels are set. The setting of alarm levels plays a vital role in a machinery condition monitoring and diagnostics system. If they are set too low, a high percentage of plant machinery will be in alarm. Data gathering time will be wasted collecting unnecessary diagnostic data, analyst time will be wasted on reviewing mounts of reports and plots, and repair time may be wasted on unnecessary procedures. Conversely, if they are set too high, a problem may be missed and an opportunity to reduce cost or save production lost. In this research, the better method of setting alarm thresholds to decrease the ratio of false alarm was found from the statistical aspect. The octave band method is suggested for use as the alarm level instead of broadband method. Three artificial fault simulations are then conducted by using the damaged parts of a rotor kit to compare the 1/1 octave band method with the broadband method. The results show that the 1/1 octave band method is more sensitive to the changes in VdB level than the broadband method.