Total downtime

Set up a mechanism for analyzing service reports so as to determine response times, time to repair, and total downtime. 

Accumulated machine repair time 7 v(/) by moment t represents the effect of a machine s operating time on its availability and total downtime due to breakdowns. The total repair time depends on the number and labour intensity of the repairs and includes an important factor-the low availability of spare parts for older, antiquated or long ago phased out equipment. 

We now tabulate the total downtime costs, holding costs and total costs in Table 4. For comparison, we have also tabulated the costs obtained using simulation. Based on the tabulated data we can already... 

In classical maintenance optimization the objective is to find the optimal interval for maintenance of single components. In multi-component systems, like a gas lift compressor, there are dependencies between the maintainable components. The total downtime may then be reduced if components are maintained... 

Availability or operating reliability is the actual operating time of a plant in relation to overall time. Usually it is stated as a percentage and relates to 8760 hours/ year, which correspond more or less to a year-round 24-hour-operation. Here, scheduled plant downtimes, e.g. for inspections, have to be taken into account Therefore, an availabiUty of 98% means that the plant may have a total downtime of 175 hours, i.e. 7.3 days. It is logical that the operator is interested in as much plant availability as possible. S/he will commit the plant constructor to adhere to availability. As a rule, penalties are provided in the case of non-compUance. Therefore, high demands on availability lead to increasing procurement and maintenance costs. In this comiection, redundancies and multi-line plants also have to be taken into consideration. 

In order to estimate the revenue losses, the total downtime of wind turbine(s) during the corrective maintenance should be estimated and to do so, expected waiting times for weather windows of given length are needed for each type of access vessel. 

Furthermore, in Figure 5 the breakdown of the total downtime is illustrated. In Figure 5 it can be observed that about half (51%) of the total downtime is caused by weather delays that corresponds to long waiting time before a suitable weather window can be found. 

It is of great interest to observe that only 15% of the total downtime is caused by the actual maintenance actions on wind farm components. 

Figure 4 shows the contribution of planned and unplanned downtime to total downtime. 

In term of results, this figure shows also that total downtime remains stable, with the two above-mentioned trends cancelling each other out. An increase was also observed in total downtime when preventive maintenance frequencies were doubled. This gives a limit that cannot be exceeded if we wish to maintain the same level of availability while reducing preventive maintenance. 

The total downtime can be estimated using Equation (8.9) below ... 

In a fixed construction, all the feeders in the switchboard, feeding the various load points, are securely mounted in the assembly and rigidly connected to the main bus. In the event of a fault in one feeder on the bus side, a shutdown of the entire switchboard may be required. A process industry or critical loads can ill afford such an arrangement. However, since this is the most cost-effective switchboard, it is also the most common type and is used extensively. It also suits all applications, except a process industry or critical loads, which may not be able to afford a total shutdown or prolonged downtime in the event of a fault. In such cases a draw-out type switchboard will prove to be a better choice as discussed below. A fixed-type construction may further be classified as follows. 

To decide which fuel to use, a host of factors must be considered. The object is to obtain high efficiency, minimum downtime, and the total economic picture. The following are some fuel requirements that are important in designing a combustion system and any necessary fuel treatment equipment ... 

Total overall performance effectiveness indicates PTPM s pursuit of maximum plant efficiency and minimum downtime. 

For part 2, for 98% conversion, each batch will require a holding time of 3.54 ksec and a downtime of 1.80 ksec for emptying, cleaning, and start-up. The total time consumed in processing one batch is thus 5.34 ksec. In order to produce 2000 kg of zeolite A per day we require that each batch contain an amount of amorphous solids equal to... 

There are three basic principles to understand and apply in value analysis and cost reduction when selecting the proper equipment. The first is that equipment costs are typically amortized over 10 years, and it is usually a small fraction of the finished product cost. The costs are typically less than 5% of the total cost per unit mass for a product. Secondly, decreasing the amount of resin in the finished product without sacrificing product quality is a major cost reduction. And finally, increasing production efficiency by increasing line speeds and decreasing downtime will decrease the cost of production. 

One of the manufacturing challenges with a full-system cleanout, is the need to interrupt manufacturing. Some fabs have installed totally redundant delivery systems, including dispense module and piping. Some adopt a scheduled downtime for system maintenance. Most simply refuse to recognize the need until disaster strikes in the form of unscheduled interruption of slurry delivery or dramatic increase in wafer defects. 

Two additional cost estimates were prepared based on ideal conditions (no downtime or a 100% online factor) and on conditions expected to be typical of a treatment process of this type (using an online factor of 75%). Total costs for the ideal case were estimated to be about 2,800,000 or 29/yd and for the typical case costs were estimated to be 3,400,000 or 36/yd (D15382M, p. 7). 

A plant operability analysis helps to establish the correct cycle time. In certain situations, the batch cycle of the entire plant is not determined by the units around the main reactor. Additional time may be needed downstream for product finishing in equipment that operates in series with the main reactor. The batch cycle time T is a composite of three contributions (1) the sum of the batch residence times t(i) in the M true batch units of the plant that operate in series (2) the sum of the residence times t(j) in the N semicontinuous trains of the plant that operate in series and (3) the sum of the downtimes t(k) in series encountered in the total batch cycle ... 

By contrast, search and retrieval in an electronic environment is said to save 10 to 20 percent of the total individual work effort required, not just the effort required to retrieve documents. In one year, an electronic system would save this company 50,000 to 100,000 person-days of effort, potentially all the time spent searching in a paper-based system and more. If network downtime is equivalent to employee downtime, comparison between the two modes of search and retrieval appears absurd. ... 

The objective value is the total maintenance cost plus economic loss (to be rninirnized). The economic loss is the loss caused by equipment failures that lead to reduced production rate or downtime. It is the economic indicator for maintenance performance, i.e. the better the maintenance plan the smaller the economic loss. Thus by rninirnizing the maintenance cost plus the economic loss, one simultaneously optimizes the cost and the performance of maintenance. 

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