An electrical power system consists of identical diesel generators, each generator. Has a constant failure rate of 0.5 per year. Calculate the reliability of the following arrangement-three months after the initial commissioning date. 1. Only one generator operating. 2. Only generator operating, one generator standby. 3. One generator operating, two generators standby.
Some basic stats. Assumptions: each of the cases are independent problems. The constant .5/year failure rate is linear throughout the year (normally a failure rate curve of machinery is like a V w/ a chopped off left side. P(Failure @ 3 Months) 0.5 / 4 .125 1) P(1 failure @ 3 months) 0.125 1-P(failure) reliability 1-.125 0.875 2) P(First fails AND seconds fails) 0.125 * 0.125 0.015625 Reliability 1 - .015625 .984375 3) P(First fails AND Second fails AND Third fails) 0.125* 0.125 * 0.125 0.00193 Reliability 1 - 0.00193 0.998047
0.5 failure per year would mean 1 failure per 2 years. Keeping the generator off for 2 years is no good, it may not start. It is best to operate the machines at least once every few months for some length of time. The longest time to failure is usually achieved by sharing the load and operating all equipment simultaneously. This method is very application dependant! Hope this properly answers your question
Not going to worry about this one but with a 50% failure, I think you outta buy Caterpillar. (You might want to fire your maintenance engineer as well)
Mark T, ia on the component of the mark. every time you alter reason tension, like from reciprocating engine to equipment field, you lose a number of that tension.and the comparable holds real with electric loss. in case you have battery's and are utilising them to go a automobile or boat, the great capability available is used quickly. subsequently an engine will recharge or a minimum of save the drain decrease, giving longer variety in a automobile. the project with boats is that's like hiking up hill all of the time, there are no longer any downhill runs that shrink the capability intake, subsequently electric capability for boats is extremely constrained, like WWII submarines of direction in case you have Nuclear capability you may circulate as long as you like, interior the layout shrink of the propulsion unit. Edit. WWII submarines had an exceptionally constrained in velocity and variety jointly as under battery capability. some thing like 4 knots an variety of 50-60 miles. in the event that they tried 8 knots they could no longer circulate very far. actually they ran on the exterior the two throughout the time of the day and at nighttime.diving purely whilst ships approached. they could make 17 knots on the exterior, so they might attempt to get previous to a convoy, then dive and anticipate the convoy to return to them. The Batteries returned then the place no longer almost effective as on the instant's batteries.
