1988

Temperature Measurement and Control

Fri, 30 Oct 2020 15:41:08 GMT

The temperature on earth varies over a wide range whereas man can only work comfortably in a quite narrow temperature range that has to be artificially maintained. In addition, many industries have extensive requirements for temperature control. Thus control engineers are called upon very frequently to design temperature control loops.

A general knowledge of control engineering is of course useful in designing temperature control loops.However, temperature control has some special features:

(i) asymmetries caused by the usually differing mechanisms of heating and cooling
(ii) complex nonlinear heat-transfer effects
(iii) highly application-dependent measurement problems.

The intention of this book is to treat the theory and practice of temperature measurement and control, and important related topics such as energy management and air pollution, at a level suitable for engineering and science undergraduate and postgraduate students, and in a manner designed to make the book valuable to practising engineers. There are no specific prerequisites for the book although a knowledge of elementary control theory could be useful.

The philosophy of the book is a compromise between fundamentals and practical guidelines. It is the author's firm belief that it is highly desirable to obtain a good insight into theoretical fundamentals (deeper than can be justified on grounds of immediate utility) before embarking on practical applications. The aim has been to produce a practically oriented text within a firm theoretical outline.

The first half of the book is an application oriented survey of temperature measurement techniques and devices. The second half is concerned mainly with temperature control in both simple and complex situations. There are chapters on heat sources, commercially available controllers, temperature control in buildings and energy conservation. The book ends with an appendix that rapidly surveys the underpinning thermodynamic theory.

Telecommunications Traffic, Tariffs and Costs

Tue, 12 Jun 2018 01:34:44 GMT

This book has been written with the intention of helping those who ore concerned with planning, ordering, managing and using telecommunications facilities in connection with their business activities, and who do not wish to obtain a detailed technical and mathematical knowledge of the subject. The various types of telecommunications traffic are analysed without recourse to the underlying theory, and the reader is introduced to the terminology and operation of modern telecommunications systems and networks. Particular attention is paid to the relationship between traffic-carrying capacity and cost, and to the importance of traffic measurement and forecasting as a means of matching equipment provision to demand. The role of performance targets is discussed and the book explains how a comparison between public-network tariff options and the cost of private system and network alternatives can ensure a cost-effective solution to any communications problem. The principles are demonstrated by simple worked examples and a detailed glossary of terms is included.

The Current Comparator

Tue, 12 Jun 2018 00:41:23 GMT

In 1961, Moore and Miljanic in collaboration with N. L Kusters developed the current comparator, for which a patent was granted in 1964. Since that time they and their associates have applied this technique toward advancing the art of electrical measurement.

The current comparator comprises a special configuration of concentric toroidal magnetic cores and windings which enable the physical realisation of a very precise ampere-turns ratio standard. It provides the basis for the precise measurement of various electrical quantities at both direct and alternating currents using current ratio techniques. Applications include the calibration of instrument transformers, measurement of the losses of high voltage capacitors and inductive reactors, measurement of the short circuit losses of large power transformers, the calibration of power and energy meters, an alternating current impedance bridge, direct current resistance measurements, the calibration of high direct current metering systems and shunts, a seven decade direct current potentiometer, and a 20 bit digital-to-analogue converter.

The book presents the basic theory of the current comparator, methods of construction leading to high ratio accuracies, and the operating principles of the various applications.

Variable Frequency AC Motor Drive System

Tue, 12 Jun 2018 00:03:20 GMT

This book is intended to explain the technical principles involved in the many AC variable speed drive systems available today. It deals with all the DC link inverter and direct AC to AC converter systems that are in commercial use. The principles of AC motors are considered specifically from the variable frequency point of view, and this chapter concentrates on the effects of harmonics. The different types of power semiconductor switches are considered separately from the drive systems in which they are used.

A total of seven separate and technically different drive systems are considered in such a way that their principles can be fully understood and their performance capabilities explained. Square wave and pulse width modulated DC link inverter systems, cycloconverters and slip power recovery drives are all included in this comprehensive book.

This book has been written so that it can be understood by general engineers, not just by experts in the field. It should therefore be of great use to any engineer involved with variable speed drives in any capacity. It should also be of interest to university and college electrical engineering departments and students.

Insulators for High Voltages

Mon, 11 Jun 2018 23:32:55 GMT

This book is a guide to the whole field of high voltage insulators as used in electrical power networks, traction and production. It covers the historical development of the shapes - sometimes strange ones - of modern types, decribes the principal materials - both ceramic and polymeric - and their fabrication, explains the physical principles of contamination and flashover, and reviews the mass of data on research and testing.

Practical advice is given, with worked examples and many illustrations, on the choice of insulator, including the problems of the environment and nuisance. The remedies that are available to deal with pollution flashover are compared and precautions are indicated for the potentially dangerous practices of live-washing and live-working.

Useful guiding principles for the designer of power lines and substations are listed with the relevant international standards and tables containing properties of materials. For the student and researcher there are accounts of current basic R&D, and indications of probable future trends. The particularly current topics of optical fibre insulation, direct current and vandal-resistance are covered.

The author's first-hand experience of most of the matters which he describes enables him to write clearly and to avoid confusing mathematical and technical complexities. This is a book for the intelligent layman as well as for the specialist.

Industrial Microwave Heating

Mon, 11 Jun 2018 23:31:51 GMT

This book offers a broad coverage of the theory and practice of industrial microwave heating. It introduces the physical processes behind dipolar and conductivity loss mechanisms and follows with a thorough presentation of dielectric property data of many industrial materials as a function of the moisture content, temperature and frequency, focussing on the interpretation of such data as regards the suitabiliy for processing these materials with microwave energy. The basic equations which govern the power dissipation, attenuation, phase constant, penetration depth and skin depth are derived from first principles while the transport equations of heat, mass and pressure are qualitatively described, giving particular emphasis to the physical mechanisms behind high frequency drying. The book provides established procedures backed by theoretical formulations for the design of industrial travelling wave and multimode applicators. It also provides extensive coverage of single mode fundamental or higher order resonant cavities and outlines a number of atypical applicator structures. It describes the essential features of processing with microwaves under vacuum and presents a brief introduction to the mechanisms which lead to gas breakdown. It stresses the need for a degree of hybridisation with other electrical or conventional heating systems and discusses a few such schemes. The book outlines a number of systems for limiting leakage from on-line industrial microwave systems and concludes with an extensive discussion of successful industrial applications.

Spherical Near-field Antenna Measurements

Mon, 11 Jun 2018 22:56:47 GMT

The subject of antenna measurements is one which has undergone revolutionary changes in recent years, in particular within space applications, where high demands are placed upon antenna design and construction.

This book represents the specific measurement technique known as the spherical near-field method. The theoretical treatment of the method is detailed but of sufficient generality to make the book useful as a basis for further research on near-field measurements and antenna coupling problems. Practical aspects of antenna test ranges, data processing schemes and measurement procedures are described. Other topics covered are measurement error analysis and generation of plane wave fields.

The authors draw on the experience from the development, sponsored by the European Space Agency, of one of the first spherical near-field test ranges. They have contributed to the establishment of spherical near-field testing as a highly accurate and versatile method, currently under implementation at test ranges worldwide.

Industrial Digital Control Systems, 2nd Edition

Mon, 11 Jun 2018 21:21:59 GMT

This book provides an introduction to the techniques employed in the design and implementation of digital control systems. The text has arisen out of a highly successful IEE Vacation School held annually at Oxford University and the contents have been tailored to a digestible level and breadth by means of the feedback provided from previous School participants. As well as a tutorial approach to the description of basic concepts and general ideas used, most chapters include numerous worked examples and details of particular applications in order to enhance the theory introduced. The importance of putting over a technique by making use of practical examples is highlighted by the inclusion of several chapters in which selected case studies are presented detailing applications of both the more conventional and the more modern digital control ideas.

The book is aimed at engineers, managers and engineering students who wish to become more widely informed about how they may employ the latest advances in digital control technology. To this end, earlier chapters concentrate on the theoretical framework of digital control, whereas later chapters concentrate on its implementation. This results in an up-to-date overview of digital control schemes which is an excellent reference text for industrialists and academics alike. This substantially revised 2nd edition (more than a third of the book is completely new) represents a distinct improvement on the extremely successful 1st edition, and bears witness to the constant modernisation required in such a rapidly changing area.

Implementation of Self-tuning Controllers

Mon, 11 Jun 2018 21:21:28 GMT

This text is an extremely useful guide for those wishing to investigate the application of self-tuning control systems. The contents have been chosen in order to restrict the amount of theoretical detail to that necessary for explanation purposes, whilst application examples and programming suggestions are highlighted. The overall text is suitable for those wishing to gain the flavour of adaptive control, although those already familiar with selftuning techniques will find the problem solutions discussed to be most attractive. Parameter estimation, numerical solutions and software aspects are all considered at length, while simplified procedures and predictive self-tuning schemes are shown in terms of fundamental concepts.

The level of the book is such that practising control engineers and postgraduate or final year control, engineering or cybernetics students would find it most suitable. A certain amount of basic digital/sampled data control systems terminology is assumed, although this does not mean that the reader needs to be familiar with more mathematical ideas, such as discrete transform methods or statistical theory. The text could be used as the foundation of a Masters course module, particularly if an emphasis is placed on the practical aspects of self-tuning control.

The book is an ideal source for those interested in self-tuning and adaptive control, and contains many useful suggestions for future trends, research directions and implementation/ application possibilities.