Engineering electrical

Electrical contacts for high-frequency switching (W). Tungsten is an ideal contact material for switches with high operation frequency, such as car horn contacts, ignition 

FIGURE 7.3. Triple-coil tungsten electrodes coated with emissive material, used in low-pressure sodium lamps [7.10]. By courtesy of Philips Lighting B.V., The Netherlands. 

Typical shapes used in high-voltage switches are shown in Fig. 7.6. 

FIGURE 7.5. Thoriated tungsten cathode (left) and thoriated tungsten anode (right) for xenon short-arc lamps used for wide-angle cinema projection. By courtesy of Plansee AG, Austria. 

FIGURE 7.6. Contacts for high-voltage switch gear. By courtesy of Plansee AG, AusOia. 

Electrical engineering is associated with the application of electrical and magnetic principles to the design, analysis, and performance of devices and services. This covers a very broad set of subtopics. In most technical universities, the largest engineering department is that concerned with electrical-related subjects. 

Subjects diat are basic to all of these endeavors include  

Since the design and application of electronic computers had their origin in electrical engineering departments, computer engineering subjects are sometimes taught in electrical engineering departments. 

However, as eomputer activity has inereased, computer seienee and engineering are usually eovered in separate departments in mostteehnieal universities. In this ehapter, an overview of a few of the major topies of importanee to eleetrieal engineering is given. 

The largest of all engineering branches, electrical engineering is concerned with electrical devices, currents, and systems. Electrical engineers work with equipment ranging from heavy power generators to tiny computer chips. Their work contributes to almost every sector of society electrical appliances for homes, electronic displays for business, lasers for industry, and satellite systems for government and businesses. 

Electrical engineers usually work in one of six specialty areas  

One of the most vibrant specialties in electrical engineering is the field of electronics. Generally speaking, this field deals with the emission, behavior, and effects of electrons. Electronics engineers design efficient circuits using a variety of electric elements that can produce, amplify, detect, or rectify electrical signals. 

Electronics has applications in communications, power, transportation, medicine, and many other fields. With the advent of transistors, semiconductor diodes, integrated circuits, and lasers, electronic technology has changed dramatically in recent years. These and other advances provide even greater opportunities for rewarding work for electrical engineers in the field of electronics. 

Electrical engineers have made and continue to make significant contributions to the field of communications. They use their knowledge of wave propagation, electromagnetic theory, and electronic principles to design radio, telephone, television, and satellite communication systems. Approximately 7 percent of electrical engineers work in the communications specialty. 

DIN EN 60811 [331] includes specifications for testing the aging of plastics insulations, sheathing, and cable-element materials in electrical and fiber-optic cables for power distribution and communication facilities, including cables used onboard ships. 

Process plants are for the most part dependent on electric power for motive purposes, to drive the process equipment and the materials transport systems. Other types of driver, in particular the steam turbine, have sometimes been employed, especially for major drives such as turbo-compressors (with which a turbine driver has a natural compatibility in terms of speed and speed variation), and in plants where steam is generated for process consumption or as a by-product in waste-heat boilers. Gas engine drivers (for reciprocating compressors) and gas turbines (for turbo-compressors) are also often employed for 

The start-point for electrical design is the electric motor and other consumers list. This list is typically drawn up by process and mechanical engineers involved in the selection of the driven equipment. The electrical engineer needs to probe this data and understand how it was drawn up, with special reference to the expected load factors (namely, ratio of actual kW or kVA to the value used as design basis). Rarely, drive sizes are underestimated. More usually, they are consistently overestimated as a result of the practice of putting factors on factors . There may be a factor of conservatism for increased process performance requirements, a factor for driven-machine performance tolerances and deterioration of efficiency, and then perhaps a factor to allow for uncertainty, and, then again, rounding up to the nearest standard motor size. 

Whereas individual motors tend to be oversized rather than undersized, it is more common to make insufficient allowance for increased numbers of drives, both as project designs develop and for the future. When deciding on criteria for future additional drives, it is often more illuminating to review past experience of project design and plant development than to rely exclusively on the process technologist. 

Sometimes the detailed electrical design commencement is attempted 

The next fundamental design document for plant electrical engineering is the single line diagram, very much the electrical equivalent of the flowsheet. This document is not the exclusive preserve of the electrical engineer it requires the input of the process and mechanical engineers. Its format is dependent on the following. 

The supply of the individual drives occurs from the plug-in modules via motor cables laid in bundles in cable routes and ending at the terminal box of the electric motors. 

Note In many plants, motor cables represent the main fire had. Often there are hundreds of kilometres of PVC-encased electric cables laid in a process plant 

The further execution of the electrotechnical equipment lies in the hands of the electrical engineers. 

At first, all measuring points of the plant have to be Usted. Again the CAD-system can generate a measuring point list from the P I diagrams which contains 

0Z Srtui-on Vflfvo AoecAOl AA001 Ccnd. Pump S iut olf at Press. SiDB Moior EMC 0.12 0.53 1.5 25 400 OC IP55 A ON 40 PN 25 3.335  

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Karlstrdms, M., Magnusson Seger, M., Crack estimation with linear filtered tomosynthesis , ISSN 1400-3902, Dept of Electrical Engineering Linkoping, Sweden (1998). 

Tu K-N, Mayer J W and Feldman L C 1992 Electronic Thin Film Science for Electrical Engineers and Materials Scientists (New York Macmillan)... 

William T, Coffey, Department of Microelectronics and Electrical Engineering, Trinity College, University of Dublin, Dublin, Ireland... 

James F. Leathrum and John A. Board. The parallel fast multipole algorithm in three dimensions. Technical report. Dept, of Electrical Engineering, Duke University, Durham, 1992. 

Apart from the well-known journals covering aspects of chemistry, physics, biology, medicine, geology, environmental science, electrical engineering, and forensic science, which all have occasional articles that use mass spectrometry for analytical purposes, the following journals frequently contain papers in which mass spectrometry plays a major role ... 

M. Tahan, Weathering of Plastics and Rubber, International Symposium of the Institute of Electrical Engineers, Eondon, June 1976, Chamelon Press, Ltd., London, 1976, p. A2.1. 

S. Shibata, T. Kitagawa, and M. Horiguchi, "WhoUy Synthesized Fluorine-Doped SUica Optical Fiber by the Sol-Gel Method," in Technica/Digest of the 13th European Conference on Optica/ Communication, He/sinki, Fin/and, Association of Electrical Engineers of Finland, Helsinki, 1987, pp. 147—150. 

J. Brice and P. Capper, eds.. Properties oJhAercury Cadmium Te//uride Institution of Electrical Engineers (INSPEC), London, 1987. 

INSPEC, E/ectronic Materia/s Information Series Institution of Electrical Engineers, London. 

A Greenwood, Vacuum Switchgear, Institution of Electrical Engineers, 1994. 

R. H. SchaUenberg, Bottled Energy Electrical Engineering and the Evolution of Chemical Energy Storage, American Philosophical Society, Philadelphia, Pa., 1982. 

Electrical engineering Equipment design Expert systems Extraction Failure analysis Flow analysis Safety... 

Department of Power Energy, Faculty of Electrical Enginering,... 

Microprocessor Application Programme. Department of Electrical Engineering, Indian Institute ofTechnology, Delhi, India,... 

Jain, MR, Proximity Effects of Busbars, ME thesis. Electrical Engineering Department. University of Roorkee, Roorkee, India (1969). 

The Berlin City electrical engineer M. Kallmann reported in 1899 on a system for controlling stray currents of electric railways [64]. As early as 1894, the Board of Trade in London issued a safety regulation for the British electric railways which specified a potential differential of not more than 1.5 V where the pipeline was positive to the rails, but 4.5 V with the rails positive. Extensive research was undertaken on reducing the risk of stray current in the soil by metallic connections from pipes to rails. However, as one writer noted, a procedure on these lines should definitely be discouraged as it carries the seed of its own destruction [64]. 

The processes of cathodic protection can be scientifically explained far more concisely than many other protective systems. Corrosion of metals in aqueous solutions or in the soil is principally an electrolytic process controlled by an electric tension, i.e., the potential of a metal in an electrolytic solution. According to the laws of electrochemistry, the reaction tendency and the rate of reaction will decrease with reducing potential. Although these relationships have been known for more than a century and although cathodic protection has been practiced in isolated cases for a long time, it required an extended period for its technical application on a wider scale. This may have been because cathodic protection used to appear curious and strange, and the electrical engineering requirements hindered its practical application. The practice of cathodic protection is indeed more complex than its theoretical base. 

If not available and the driver is a motor, the local electrical engineers may be coerced into procuring accurate current (CT) and potential (PT) transformers to permit the use of watt meters. The everyday plant CTs and PTs aren t suitable for a quantitative field test. When having to solve a compressor s performance, one will use what is available, but only because it is expedient. 

Electrical engineering, including wiring devices, and electronics 40% Domestic appliances pot and pan handles and tableware 33%... 

Department of Electrical Engineering and Computer Science and Department of Physics Massachusetts Institute of Technology,... 

Figure 14.1. Estimated emphasis on three broad fields - Werkstoffwissenschaft = materials science Maschinenbau/E-technik = mechanical and electrical engineering Physik-Chemic = physics and chemistry - in MSE education at various German universities from (DGM 1994).

A number of somewhat more specialised texts also began to appear, such as Anderson and Leaver s Materials Science (1969) in spite of its broad title, this book by two members of the Electrical Engineering Department at Imperial College, London, was wholly devoted to electrical and magnetic (functional) materials. So... 

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