s from: Introduction to reliability Engineering by Charles Ebeling 1. In a reliability testing, it is of interest to know how long the test must run in order to generate a specific number of failures. A new condenser fan motor is believed to have a constant failure rate of 3.4 failures per 100 operating hours. A single test stand is to be used in which a motor is operated until failure and then replaced with a new motor from production. What is the expected test time if 10 failures are desired? 2. Repetitive loading. A packaging machine (Cartoner) in a food processing facility will jam with a constant probability into a single case for shipment to buyers. The production rate is 3o cans of coffee every minute. What is the probability (Reliability) of no jams during 1- hr. production run? 3. A landing system has repetitive stresses placed on it twice a day as result of landings. The probability of a failure during landing is 0.0028. Determine the reliability of the landing gear system over a 30 day contingency operation. What is the probability of a failure occurring between days 10 and 20 of the operation? 4. Specifications for a power unit consisting of three independent and serially related components (failure modes) require a design life of 5 yr with 0.95 reliability. a) Let each component have a constant failure rate such that the first component's rate is twice that of the second and the third component's rate is three times that of the second. What should be the MTTF of each component and the system b) If two identical power units are placed in parallel, what is the system reliability at 5 yr, and what is the system MTTF. Consider two redundant components having a constant but different failure rates. a) Derive the reliability function and the MTTF b) Find the reliability at 1000hr and the MTTF of a two -component redundant system where per hour and per hour