19 Reliability Supplement to Chapter Four a mearn ervice life that can be modele

Question

19

Reliability Supplement to Chapter Four a mearn ervice life that can be modeled by a normal distribution with a mean of six years and deviation of one-half year 17 ajor television manufacturer has determined that its 40-inch LED televisions have ard a. What probability can you assign to service lives of at least (1) five years? (2) six years? (a seven and one-half years? b. I t the manufacturer offers service contracts of four years on these televisions what can be expected to fail from wear-out during the service period? 18. Refer to Pro blem 17. What service period would achieve an expected wear-out rate of cent? (2) 5 percent? 9. Determine the availability for each of these cases MTBF 40 days, average repair time 3 days b. MTBF 300 hours, average repair time 6 hours 20. A machine can operate for an average of 10 weeks before it needs to be overhauled, a process which takes two days. The machine is operated five days a week. Compute the availability of this machine. (Hint: All times must be in the same units.) 21. A manager must decide between two machines. The manager will take into account each machine's operating costs and initial costs, and its breakdown and repair times. Machine A has a projected average operating time of 142 hours and a projected average repair time of 7 hours. Projected times for machine B are an average operating time of 65 hours and a repair time of 2 hours. What are the projected availabilities of each machine? 22. A designer estimates that she can (a) increase the average time between failures of a part by 5 per and s have an average life of 2.7 years. Battery life is normally distributed with a meanof of S450, or (b) reduce the average repair time by 10 percent at a cost of $200. Whi ent at a cost option would be more cost-effective? the average repair time is 4 hours Currently, the average time between failures is 100 hour 23. Auto batterie 2.7 years and a standard deviation of.3 year. The batteries are warranted to operate for a minimu of 2 y charge. The com ears. If a battery fails within the warranty period, it will be replaced with a new battery pany sells and installs the batteries. Also, the usual $5 installation charge will ved wai a. b. A competitor is offering a warranty of 30 months on its premium battery. The manager of t What percentage of batteries would you expect to fail before the warranty period expires ompany is toying with the idea of using the same battery with a different exterior, labeling as a pre pany have to charge on its "premium" battery to offset the additional cost of replacing batt it mium battery, and offering a 30-month warranty on it. How much more would the con c. What other factors would you take into consideration besides the price of the battery? atteries?

Explanation / Answer

Availability = MTBF/(MTBF+MTTR)

a) MTBF = 40 days, MTTR = 3 days

Availability = 40/(40+3) = 93.0%

b) MTBF = 300 hours, MTTR = 6 hours

Availability = 300/(300+6) = 98%

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.