Standby component

Systems are generally made up of components which must be operating in order for the system to fulfil its mission (continuous and intermittent duty components), standby components which take over the function of the operating component if it should fail and the components of the monitoring and safety systems. The latter only have to function on demand. Therefore they also belong to the class of standby components. 

In this figure the circles represent the potential states of the component (standby, hidden failure, and repair) and the rectangles the transitions (that is to say events) that may occur. The token (small black circle) indicates the actual state of the component and which transitions are vahd (i.e. corresponding to events that may occur) at every moment. When a transition is fired one token is removed from the places upstream, and a token is added in each of the downstream places and assertions (represented by ) are updated. 

First, the old standby methods of checking the overall individual component balances and checking dew and bubble points will help verify distillate and bottoms concentrations. The total overhead (distillate plus reflux) calculated dew point is compared to the column overhead observed temperature and the bottoms calculated bubble point is compared to the column bottom observed temperature. If the analyses are not felt to be grossly in eiTor. the following method wfill also prove very helpful. 

Standby Failure. Some systems or components are normally in standby, but must operate when demanded. Because they are on standby, their failed state will be unknown unless it is caught by testing. This is standby failure. ... 

Operating mode The operational service the equipment primarily experiences expressed as alternating, running, or standby modes and reflected in the exposure hours or demands of that component. 

Test demands Periodic equipment testing is an important source of demands, especially for safety system components that are often in a standby state. A review of the test procedures can be performed to obtain this information if it is not recorded in the maintenance records. 

This chapter introduces the basic items of design and specification for the principal systems and components of an electrical industrial installation. Electrical supply systems are discussed with regard to interface with the supply authorities and the characteristics. Salient features of switchgear, transformers, protection systems, power factor correction, motor control equipment and standby supplies are identified and discussed together with reference to the relevant codes of practice and standards. The equipment and systems described are appropriate to industrial plant installations operating at typically 11 kV with supply capacities of around 20MVA. 

July 2006 I would like to know how to calculate the minimum load current which an SMPS can deliver, in order that its regulation is still OK. Indeed, I would like to use the 2594HV for my design. This power supply is always going to be active. What happens when the different components (loads, etc.) connected to this regulator s output are in standby mode and only consume about lOOuA Will the regulator still work What is the consumption of the chip in such a mode Thank you. 

A power failure exceeding the time limit is most critical during MD. In this case a standby power generator with a start up time of e. g. 1 min either for the operation of the whole plant or at least for the critical components is the only answer. The sequence of importance for the components can be ... 

The main and standby oil pumps shall have steel casings unless they are enclosed in a reservoir. All other oil containing pressure components shall be steel. (See 3.5.5 for requirements for lubricating oil piping.)... 

Errors that resulted in the component being unavailable when needed—For example, equipment not restored to full operability following maintenance, testing, or inspection. Valves left closed, actuation or protective systems not reconnected, slip-blinds left in the line, or failing to return pump selector switches to the standby auto-start position are common examples. 

Based on the studies three pilot plants are proposed and analyzed for three oil platforms at Neft Dashlari. All plants are integrated system with three main components (1) a wind generator (8 m diameter wind turbines) to produce primary energy, (2) a standby diesel-electric set, to cover the lack of energy during calm periods, and (3) a storage battery bank to cover daily imbalances between power production and power load during the day. 

Periodically tested standby components PTS 1 - p AsTs Q = 1 + As Tr As Ts Xs = Failure rate during standby Ts = Time between test Tr = Average reparation time Q = Unavailability... 

If components of the equipment fail they will be detected by the survey measurements suggested above. Standby components or spare parts are to be specified as for any other industrial plant. 

Oil, used for lubricating the gears and bearings, is separated from the compressed airstream by labyrinth seals. Shown in Figure 3.31, the seals consist of two separate components, an air seal and an oil seal. In between the two, the seal is open to atmosphere. Any oil bypassing the oil seal leaks to atmosphere. The air seal is always at a higher pressure so that any leaks are always from air to atmosphere and oil cannot enter the process fluid. Oil is typically provided by a shaft-driven pump with a standby motor-driven pump available. 

This function includes all information about the operational status and maintenance of equipment, vehicles, and facilities. Operational status refers to an availability state (in active service, ready, standby, in/awaiting maintenance, etc.), along with total time in service, time since last regular maintenance, and so on. The ERP system tracks maintenance schedules for the equipment and actual maintenance incidents, both preventive and remedial, and typically an attention list of things that may need inspection and refit. Any maintenance activities include both technical data (nature of fault, repair or change, parts installed, named services performed, etc.) and administrative data (authorization, execution team, date and time, etc.). In addition, this component tracks the schedules, labor, and work assignments of maintenance teams, external maintenance contracts and calls, and actual or assigned costs of maintenance activities. 

Active redundancy or hot standby The component has the same failure rate as if it was operating in the system. 

Passive redundancy, spare, or cold standby The standby component cannot fail. This is generally assumed of spare or shelf items. 

Warm standby The standby component has a lower failure rate than the operating component. This is usually a realistic assumption. 

ColdFusion (programming language), 78-79 Cold heading, 1319, 1321 Cold molding, 1325, 1326 Cold standby components, 1933 CoUaboration(s) networked, 234 strategic, 34 types of, 604, 605... 

Hot-formed components, 568, 581-585 axial die rolling, 584 extrusion, 582-584 precision forging, 581-583 Hot isostatic pressing (HIP), 572—574 Hot standby, 1933... 

A technical system normally has a number of standby components (components which become active only after demand). Components of the monitoring and safety systems belong to this category. These systems are devised to cope with accident initiating events. They form the barriers between the initiating and the undesired event. The latter only occurs if all barriers fad. The situation is shown schematically in Fig. 9.10. Obviously in the same system initiating events can occur for whose control various barriers may become effective, and initiating events which directly lead to the undesired event, for example the spontaneous failure of a chlorine pipe. 

The number of barriers depends on the number of redundant standby components in the monitoring and safety systems, which can become effective in case of the initiating event under investigation. If components from barriers have to fail before the undesired event occurs, their failure is connected with the initiating event by an AND -gate. 

If, on the other hand, component behaviour is described by a failure rate the assumption is that corrosion, dirty environment etc. are at the root of failure. Such influences are also present during standby of components (e.g. those of safety systems). If they then cause a failure it manifests itself only on demand. Therefore frequently failure rates are also used to describe standby components. However, the numerical values may differ from those applicable to their operating phases. 

Structures, systems and components important to safety vhich are installed as redundant items, or are called upon when normal operating conditions are threatened or lost, are normally kept in standby or off-line states. Examples of such SSCs are reactor containment vessels, emergency electric power sources, isolation valves and safety valves. Some of these SSCs cannot be monitored in situ for their operating reliability. Testing and surveillance for the actual conditions under which they are expected to operate, and which are generally difficult or impossible to reproduce, are usually undertaken under simulated conditions. These simulated conditions should be carefully planned, and the results should be interpreted prudently. 

Where certain redundant systems and components are kept on standby, operation of these systems and components should be rotated in order to subject all components to similar operating times and thus to similar surveillance procedures and frequencies. Maintenance intervals should be adjusted to ensure that not all systems and components wear out at the same time. 

This economical test exposes die climatically unstable points of electronic components. Due to the nature of the test, the entire board is evaluated. This test accelerates the mechanisms of electrochemical migration. Consequently, faults that previously would appear after months or even years can be detected during the development process. To identify potential weak points, the assembly is operated in standby mode and immersed in deionized water. Testing while the assembly is in full operation is even more effective. The sensitivity of the circuit to moisture exposure is assessed on the basis of flie recorded test current, combined with a subsequent examination of the assembly. Through weak point analysis, a Yes/No decision can be determined concerning the expected service life, of the assembly. 

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