Search results

1 – 10 of over 33000
To view the access options for this content please click here
Article
Publication date: 1 January 2014

Sanmugasundaram Thirukumaran, Paul Ratnamahilan Polycarp Hoole, Harikrishnan Ramiah, Jeevan Kanesan, Kandasamy Pirapaharan and Samuel Ratnajeevan Herbert Hoole

As commercial and military aircraft continue to be subject to direct lightning flashes, there is a great need to characterize correctly the electrical currents and electric

Abstract

Purpose

As commercial and military aircraft continue to be subject to direct lightning flashes, there is a great need to characterize correctly the electrical currents and electric potential fluctuations on an aircraft to determine alternative design approaches to minimizing the severity of the lightning-aircraft dynamics. Moreover, with the increased severity of thunderstorms due to global warming, the need arises even more to predict and quantify electrical characteristics of the lightning-aircraft electrodynamics, which is normally not measurable, using a reliable electric model of the aircraft. Such a model is advanced here. The paper aims to discuss these issues.

Design/methodology/approach

The case considered in this paper is that of an aircraft directly attached to an earth flash lightning channel. The paper develops a new approach to modelling the aircraft using electric dipoles. The model has the power to represent sharp edges such as wings, tail ends and radome for any aircraft with different dimensions by using a number of different sized dipoles. The distributed transmission line model (TLM) of the lightning return stroke incorporating the distributed aircraft model is used to determine aircraft electrical elements and finally the electric current induced on the aircraft body due to lightning's interaction with the aircraft. The model is validated by the waveform method and experimental results.

Findings

The dipole model proposed is a very powerful tool for minute representation of the different shapes of aircraft frame and to determine the best geometrical shape and fuselage material to reduce electric stress. This charge simulation method costs less computer storage and faster computing time.

Originality/value

The paper for the first time presents a computer-based simulation tool that allows scientists and engineers to study the dynamics of voltage and current along the aircraft surface when the aircraft is attached to a cloud to ground lightning channel.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 1/2
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 1 June 2000

K. Wiak

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction…

Abstract

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 1 June 2000

A. Savini

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic…

Abstract

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 1 December 1935

W.E. Crook

THE electric current is often compared, especially in “ popular ” works, to the flow of water in a pipe. This conception holds good in certain respects, but is definitely…

Abstract

THE electric current is often compared, especially in “ popular ” works, to the flow of water in a pipe. This conception holds good in certain respects, but is definitely misleading in many ways. The ground engineer who wishes to obtain the “ X ” licence for electrical equipment need not, it is true, make such a close study of the fundamentals of electricity and magnetism as the electrical engineer or science degree student would have to do. Nevertheless, in order to understand the operation and maintenance of electrical apparatus, however simple, some theoretical knowledge is necessary. In electrical work, the beginner is confronted with one special difficulty—the absence of moving parts—and this difficulty seems to be most formidable to men who have been accustomed in their daily work to think in terms of crank‐shafts, gear‐wheels, cams, valves, push‐rods and all the other apparatus of mechanical engineering. To put the situation into a phrase, the beginner wants to “ see the wheels go round,” and is naturally somewhat baffled when he discovers that there are no wheels to go round. Some imagination is, therefore, necessary in studying electrical phenomena, and the student, particularly the engine fitter, must school himself to avoid the futile applica‐tion of well‐absorbed mechanical principles to apparatus in which they have no application.

Details

Aircraft Engineering and Aerospace Technology, vol. 7 no. 12
Type: Research Article
ISSN: 0002-2667

To view the access options for this content please click here
Article
Publication date: 1 August 1954

G. Mole

Stray currents in the ground are those which have their origin in electrical power and traction systems, as distinct from currents of voltaic origin. The electrical

Abstract

Stray currents in the ground are those which have their origin in electrical power and traction systems, as distinct from currents of voltaic origin. The electrical industry is concerned with the control of such stray currents, partly because of its awareness of responsibility towards the authorities operating other underground services, and partly because of its own very large capital investment in underground cables, for which even a low incidence of corrosion would represent a serious economic and operational drawback. The following article is a brief review of the existing techniques for the survey and control of stray current corrosion, cathodic protection being an important method of control.

Details

Anti-Corrosion Methods and Materials, vol. 1 no. 8
Type: Research Article
ISSN: 0003-5599

To view the access options for this content please click here
Article
Publication date: 6 July 2012

Vesna Arnautovski‐Toševa, Khalil El Khamlichi Drissi and Kamal Kerroum

The purpose of this paper is to present a frequency domain analysis of high frequency behaviour of an indoor Powerline communications (PLC) circuit in the presence of a…

Abstract

Purpose

The purpose of this paper is to present a frequency domain analysis of high frequency behaviour of an indoor Powerline communications (PLC) circuit in the presence of a plaster board/concrete wall structure. The main purpose of this analysis is to investigate the influence of the wall structure on the current distribution and the radiated electric field due to PLC signals in range from 3 MHz to 30 MHz.

Design/methodology/approach

The mathematical model is based on the full‐wave theory formulated by the Mixed Potential Integral Equation (MPIE) for the electric field due to energized thin‐wire conductors in stratified media. The solution for the current and the electric field distribution is obtained by using the Method of Moments.

Findings

Numerical results are obtained of the current distribution along the conductors of the PLC circuit and the radiated electric field in presence of a wall structure. Two cases are analyzed: when the circuitry is placed in the wall; and when the circuitry is placed outside the wall.

Practical implications

The paper presents the mathematical model that may be applied for analysis of indoor PLC circuits placed in presence of wall structures.

Originality/value

In the paper, a full‐wave model of the PLC circuitry in presence of a wall structure is developed, on the basis of MPIE and the Method of Moments.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 16 October 2018

Lina Si, Yan Pan, Xiaoqing Zhang, Jie Wang, Jia Yao, Yanjie Wang, Fengbin Liu and Feng He

This paper aims to clarify the effects of metallic nanoparticles (NPs) additives and room temperature ionic liquids (ILs) on the tribological performance of electric contacts.

Abstract

Purpose

This paper aims to clarify the effects of metallic nanoparticles (NPs) additives and room temperature ionic liquids (ILs) on the tribological performance of electric contacts.

Design/methodology/approach

Tribological properties of copper (Cu) and silver (Ag) NPs as lubricant additives in different lubricants of ILs or polyalphaolefin (PAO) oils under applied electric currents were investigated. After tribological tests, morphologies of worn surfaces were observed; meanwhile, lubrication and anti-wear properties were analyzed.

Findings

The mixture solution of the IL and Cu NPs showed desirable lubrication and anti-wear properties due to the reduction of electrocorrosion and the enhancement of rolling effects of particles in the contact region. The anti-wear performance of Cu NPs is better than that of Ag NPs due to the difference in the particle size. The PAO oil with the Cu NPs additives showed poor lubrication properties due to the low solubility of the particles in the oil. When the direction of applied current was changed, the friction of the lubricant with better conductivity was more stable in the variation trend.

Originality/value

This paper begins with a study of tribological properties of Cu and Ag NPs as lubricant additives in different lubricants of IL or PAO oils under applied electric currents. The authors then propose several methods and possible solutions which could be implemented to improve the tribological performance of electric contacts.

Details

Industrial Lubrication and Tribology, vol. 70 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article
Publication date: 16 March 2010

Yi Lin and Xiaoya He

The purpose of this paper is to use the general systemic yoyo model to illustrate why electric fields and magnetic fields can manifest each other and interact with each other.

Abstract

Purpose

The purpose of this paper is to use the general systemic yoyo model to illustrate why electric fields and magnetic fields can manifest each other and interact with each other.

Design/methodology/approach

The coordinated interaction of eddy and meridian fields of spinning yoyos is employed as our methodology for the investigation in this paper. At the end, the First Law on State of Motion is beautifully utilized.

Findings

Among many new theoretical discoveries, systemic yoyo models are provided to understand electric currents and the induced magnetic fields, which lead to a distinction between the yoyo structures of permanent magnets and those of the magnetic field induced by electric currents. It is theoretically shown why all fields in nature, such as electric, magnetic, universal, gravitational, and nuclear fields, have to exist in pairs of opposite polarities, even though one polarity might not be visible or recognizable with the current technology. Using the quark structures of spinning yoyos, an explanation is provided for why protons carry positive electric fields, while neutrons are electrically neutral.

Originality/value

One of the originalities of this paper is about its unified theory underlying many observed phenomena of electric and magnetic fields.

Details

Kybernetes, vol. 39 no. 2
Type: Research Article
ISSN: 0368-492X

Keywords

To view the access options for this content please click here
Article
Publication date: 10 April 2007

G.B. Kumbhar, S.V. Kulkarni, R. Escarela‐Perez and E. Campero‐Littlewood

This paper aims to give a perspective about the variety of techniques which are available and are being further developed in the area of coupled field formulations, with…

Abstract

Purpose

This paper aims to give a perspective about the variety of techniques which are available and are being further developed in the area of coupled field formulations, with selective bibliography and practical examples, to help postgraduate students, researchers and designers working in design or analysis of electrical machinery.

Design/methodology/approach

This paper reviews the recent trends in coupled field formulations. The use of these formulations for designing and non‐destructive testing of electrical machinery is described, followed by their classifications, solutions and applications. Their advantages and shortcomings are discussed.

Findings

The paper gives an overview of research, development and applications of coupled field formulations for electrical machinery based on more than 160 references. All landmark papers are classified. Practical engineering case studies are given which illustrate wide applicability of coupled field formulations.

Research limitations/implications

Problems which continue to pose challenges to researchers are enumerated and the advantages of using the coupled‐field formulation are pointed out.

Practical implications

This paper gives a detailed description of the application of the coupled field formulation method to the analysis of problems that are present in different electrical machines. Examples of analysis of generators and transformers with this formulation are presented. The application examples give guidelines for its use in other analyses.

Originality/value

The coupled‐field formulation is used in the analysis of rotational machines and transformers where reference data are available and comparisons with other methods are performed and the advantages are justified. This paper serves as a guide for the ongoing research on coupled problems in electrical machinery.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 18 September 2007

K. Zakowski

This paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis.

Abstract

Purpose

This paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis.

Design/methodology/approach

Results were obtained from investigations performed in the presence of a generated electric field with controlled variable characteristics, and in the presence of an electric field generated by a tramline. The analysis of measurement registers was performed using Short‐Time Fourier Transformation. The results were presented in the form of spectrograms, which illustrate changes in the spectral power density of the measured signal versus time.

Findings

Tandem time/frequency analysis reveals the random or deterministic character of the electric field, enabling its complete time/frequency characteristics to be obtained. Such information is inaccessible using exclusively the frequency analysis methods that utilize classical Fourier transformations. Moreover, an analysis of the spectral power density distribution of the signals in three directions on the ground surface makes it possible to define the localization of the field source.

Practical implications

Analysis methods for electric fields in the ground should be adapted to the evaluation of non‐stationary signals because the stray currents are of this type. Such a possibility is given by combined analysis in the domains of time and frequency. This method can be used as complementary to applied measurement techniques of stray current interference.

Originality/value

The method of electric field detection and characterization, as related to stray currents, previously has not been presented in the literature. This method of signal analysis may be adopted for other investigations that are reliant on the registration of voltages or potentials characterized by arbitrary frequencies.

Details

Anti-Corrosion Methods and Materials, vol. 54 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

1 – 10 of over 33000