Availability

2016 ◽  
pp. 339-371
Keyword(s):  
Electric Power ◽  
Electromagnetic Interference ◽  
Power Converters ◽  
Operating Voltage ◽  
Repairable Systems ◽  
Alarm Management ◽  
The Subject ◽  
Influence Of Noise ◽  
Catastrophic Faults

Protection methods, which were described in the previous chapter, save the converter against non-catastrophic faults. However, this method saves the converter but it also takes the converter out of the service. The subject of this chapter is converters that are not damaged but can not operate normally. In this chapter, availability of electric power converters as a most important but usually forgotten parameter is described. The concept of availability was originally developed for repairable systems that are required to operate continuously. It is explained that a system may be unavailable while none of its parts damaged. In fact, there is an important difference between reliability and availability. A converter may be highly reliable but unavailable and vice versa. One of the most important factors for this undesired state is influence of noise. In this chapter, electromagnetic interference and certain methods for reducing its undesired effects on electric power converters are presented. Electric power converters are usually the source of electromagnetic noise due to high operating voltage and/or current. Various techniques for safe operation of sensitive systems that operate close to these converters are described. In the last part of chapter, alarm management is presented based on availability concept. This method is used to prevent fast shutdown of important systems due to dispensable faults.

Fault Mechanism

2016 ◽  
pp. 62-118
Keyword(s):  
Electric Power ◽  
Electromagnetic Interference ◽  
Power Converters ◽  
Failure Process ◽  
Destructive Effect ◽  
Special Factor ◽  
Main Factors ◽  
Fault Mechanism ◽  
Failure Factors

Static and rotary electric power converters have different structures but there are common failure factors in both of them. In this chapter, causes of failure in electric power converters is described. All of the failure factors which are described in this chapter are catastrophic factors and lead to destructive damage in the systems. Other types of failure without destructive effect on converter like electromagnetic interference will be presented in the next chapters. All descriptions are based on details of operation of the converters which were presented in the previous chapter. Over temperature, over voltage, mechanical forces and environmental effects like humidity are the main factors of failure in systems. Origins of these factors are described in this chapter. Over temperature is a special factor among them because other failure factors finally act as over temperature in failure process of the converters. Since over temperature is the main failure factor in electric power converters, loss model of components in electric power converters are presented in details. In addition, practical technique for measuring power loss is described. Sample industrial examples of damaged equipments due to these failure factors are shown to give a real sense to reader about failure results.

Extended electric power sources

2018 ◽  
Author(s):  
T.A. Konev ◽  
V.A. Kuzmin ◽  
E. Yu. Mutovina ◽  
R.D. Puzhaykin ◽  
Vladimir Salomatov
Keyword(s):  
Electric Power ◽  
Electric Current ◽  
Load Resistance ◽  
Active Power ◽  
Operating Voltage ◽  
Power Sources ◽  
Distributed Parameters ◽  
Analytical Expressions ◽  
Characteristic Resistance ◽  
Length Effects

Chemical sources of current are investigated as lines with distributed parameters. Analytical expressions are obtained for the voltage and active power values of the source at different distances from the beginning of the cell as well as dependences of the working voltage and active power on the source length. Effects of a reduction in the operating voltage and active power are due to the flow of electric current along the source during operation. The magnitude of these effects depends not only on the length of the source, but also on the ratio of characteristic resistance to the load resistance.<br>

Transaction cost economics and the firm

2020 ◽  
pp. 743-770
Author(s):  
David M. Kreps
Keyword(s):  
Transaction Cost ◽  
Transaction Cost Economics ◽  
Unit Of Analysis ◽  
The Subject ◽  
The Individual

This chapter continues the discussion of the previous chapter about models of the firm, with consideration given to models where the firm is something more like a market than a consumer. It considers how a transaction placed within the context of a firm is different from the “same” transaction placed within a market, which is the subject of transaction cost economics. In transaction cost economics, the unit of analysis is the individual transaction. In this theory, firms are not entities, things of the rough category of the consumer; instead firms are institutions, in the rough category of the market. The line between firms and markets is rather fuzzy, but what line there is is drawn along the dimension of the frequency of interaction, the relative permanence of certain legal and market relationships, and the extent to which parties to a transaction are “tied” to one another.

Speech

2018 ◽  
pp. 177-190
Author(s):  
Thomas Nail
Keyword(s):  
Human Body ◽  
The Body ◽  
Spatial Description ◽  
The Subject

This chapter argues that the spatial description of being first emerged as historically dominant in the mythology and mythograms of prehistoric and Neolithic peoples, but at the same time was also inscribed on the body of the speaker of those same mythologies through speech. Therefore, the mythological description of being as space also presupposes a kinetic and historical transformation of the human body into a speaking body. The kinetic structure of this new surface of inscription is the subject of the present chapter. The thesis that follows is that the historical coemergence of spatial mythologies explored in the previous chapter and the new kinographic technology of speech follow the same dominantly centripetal field of motion during this time.

Stress Reduction

2016 ◽  
pp. 262-301
Keyword(s):  
Electric Power ◽  
Design Process ◽  
Stress Reduction ◽  
Printed Circuit Board ◽  
Power Converters ◽  
High Amplitude ◽  
Power Converter ◽  
Operating Conditions ◽  
Circuit Board ◽  
Inrush Current

After evaluation of reliability in the previous chapters and its consideration as a converter figure of merit, in this and the next chapters, guidelines for improvement of reliability are presented. These methods are used in both design and operation process of the converter. The focus of this chapter is on the component stress reduction in the design process. Based on background of chapter two, reliability of a converter increases if it operates at a set point with low stress. It is assumed that the converter is under design process or operates without fault. The methods for reliability improvement in faulty converters are discussed in the next chapters. In this chapter, methods for reducing electric field are described at both system and printed circuit board level. Low temperature operating conditions for an electric power converter are described and tools for this goal are presented. Series connection for voltage sharing and parallel connection for current sharing is explained. Novel control methods of power converters for reducing the complexity and reliable operation are presented. Control of inrush current as a typical transient problem in electric power converters is presented. Methods for preventing the over stress condition on the components in faulty cases are described. Techniques for reducing mechanical and environmental stress are expressed. Mechanical dampers for preventing the high amplitude vibration and insulating colors against humidity are presented. Industrial and real samples are presented to demonstrate application of the proposed methods.

Miniature turbo-Brayton technologies for space-borne thermal-to-electric power converters

2002 ◽  
Author(s):  
Mark V. Zagarola ◽  
Walter L. Swift ◽  
John A. McCormick ◽  
Michael G. Izenson
Keyword(s):  
Electric Power ◽  
Power Converters

scholarly journals Reduction in the operating voltage and active power of extended electric power sources

2019 ◽  
Vol 1399 ◽  
pp. 022011
Author(s):  
T A Konev ◽  
V A Kuzmin ◽  
E Yu Mutovina ◽  
R D Puzhaykin ◽  
V N Salomatov
Keyword(s):  
Electric Power ◽  
Active Power ◽  
Operating Voltage ◽  
Power Sources
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