Tutorial - Condition Monitoring 1. As the chief engineer of a company, you wish to install a condition monitoring (CM) system on a fleet of submersible water pumps. Table 1) shows the associated costs. Non-recurring cost Cost of infrastructure Cost of maintenance No. of maintenance ac- tions per year Table 1: Maintenance costs Condition based maintenance $300 $1200 $ 200 3 Corrective maintenance $0 $0 $ 900 2 = (1) Determine the return on investment (ROI) for the CM system for a life cycle of 5 years. 5 [ROI = 4 (ii) Would you recommend installation of the condition monitoring system? [Yes, ROI>0] 2. A maintenance department considers procuring an engineering system. Two manufacturers are bidding to provide the system and their corrective maintenance cost related data are given in Table 2 Table 3 is failure time data provided by the two manufacturers. (i) Assuming that the failure distribution of both systems is exponential, determine the annual failure rate of each system. [Ans: 2.457, 1.739 failures/yr] (ii) Determine which of the two systems will be less costly with respect to present values of maintenance and by how much? (Ans: B, KShs. 248,500.) B Table 2: Maintenance Cost-Related Data Description Manufacturer A Manufacturer System System Expected life 10 Years 10 Years Cost of a corrective maintenance KShs. 100,000 KShs. 120,000 action Annual interest rate 8% 8% Table 3: Failure times in months System A4 35.5 6.5 4.5 5.8 System B 8 6 6.4 7.5 4.5 9 3. As the chief engineer of a manufacturing firm, you are to advice the management on the equipment to purchase. Table 4 shows the maintenance cost related data are given of two equipments provided by the manufacturer. Determine which of the two systems will be less costly with respect to present values of maintenance and by how much? [Ans: B, KShs. 378,000) 4. Table 5 shows the failure pattern of 100 identical pneumatic actuators. If the cost of corrective maintenance is $120 while that of preventive maintenance is $40, calculate the optimum preventive maintenance interval. [Ans: 3 years) 5. Table G shows the failure times of identical hydraulic actuators. Assuming that failure distribution is approximated by a 2-parameter Weibull distribution, (i) Determine graphically, the Weibull parameters, and a [Ans: B=3.98, 9 =41.15 Months) (ii) If the cost of failure of an actuator is $250 and the cost of preventive maintenance is $100, using Dodson's method, estimate the optimum preventive maintenance interval. [Ans: Topt = 28 Months) Tutorial - Condition Monitoring 1. As the chief engineer of a company, you wish to install a condition monitoring (CM) system on a fleet of submersible water pumps. Table 1) shows the associated costs. Non-recurring cost Cost of infrastructure Cost of maintenance No. of maintenance ac- tions per year Table 1: Maintenance costs Condition based maintenance $300 $1200 $ 200 3 Corrective maintenance $0 $0 $ 900 2 = (1) Determine the return on investment (ROI) for the CM system for a life cycle of 5 years. 5 [ROI = 4 (ii) Would you recommend installation of the condition monitoring system? [Yes, ROI>0] 2. A maintenance department considers procuring an engineering system. Two manufacturers are bidding to provide the system and their corrective maintenance cost related data are given in Table 2 Table 3 is failure time data provided by the two manufacturers. (i) Assuming that the failure distribution of both systems is exponential, determine the annual failure rate of each system. [Ans: 2.457, 1.739 failures/yr] (ii) Determine which of the two systems will be less costly with respect to present values of maintenance and by how much? (Ans: B, KShs. 248,500.) B Table 2: Maintenance Cost-Related Data Description Manufacturer A Manufacturer System System Expected life 10 Years 10 Years Cost of a corrective maintenance KShs. 100,000 KShs. 120,000 action Annual interest rate 8% 8% Table 3: Failure times in months System A4 35.5 6.5 4.5 5.8 System B 8 6 6.4 7.5 4.5 9 3. As the chief engineer of a manufacturing firm, you are to advice the management on the equipment to purchase. Table 4 shows the maintenance cost related data are given of two equipments provided by the manufacturer. Determine which of the two systems will be less costly with respect to present values of maintenance and by how much? [Ans: B, KShs. 378,000) 4. Table 5 shows the failure pattern of 100 identical pneumatic actuators. If the cost of corrective maintenance is $120 while that of preventive maintenance is $40, calculate the optimum preventive maintenance interval. [Ans: 3 years) 5. Table G shows the failure times of identical hydraulic actuators. Assuming that failure distribution is approximated by a 2-parameter Weibull distribution, (i) Determine graphically, the Weibull parameters, and a [Ans: B=3.98, 9 =41.15 Months) (ii) If the cost of failure of an actuator is $250 and the cost of preventive maintenance is $100, using Dodson's method, estimate the optimum preventive maintenance interval. [Ans: Topt = 28 Months)