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A virtual interactive electromagnetic laboratory:an effective pedagogical approach

Prof. S. V. KulkarniDepartment of Electrical EngineeringIndian Institute of Technology Bombay, INDIA svk@ee.iitb.ac.in

Forum for Electromagnetic Research Methods and Application Technologies (FERMAT)

Presented at IEEE-INAE Symposium on Electromagnetic Education and Research

SSN College of Engineering, Tamil Nadu, IndiaDecember 12-13, 2016

mailto:svk@ee.iitb.ac.in

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Copyright

©The use of this work is restricted solely foracademic purposes. The author of this work ownsthe copyright and no reproduction in any form ispermitted without written permission by the author.

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Abstract

Electromagnetic Fields is one of the foundation courses in both Electrical and Electronics EngineeringCurricula. It is generally perceived to be a difficult-to-understand subject by the students. If theconceptual understanding is not clearly assimilated by them, the course gets shrouded in abstractnessand mathematical formulae. It is essential to explain the involved theory through visuals and real-lifepractical examples. By means of this virtual laboratory, theories in electrostatics, magnetostatics, andtime-varying fields are explained using graphical results obtained through MATLAB based codes aswell as field distributions plotted using Finite Element Method and Method of Moment basedcomputations.

This virtual laboratory has been designed by using Java Applets which can provide interactive featuressuch as radio buttons and provision for drawing contours. These applets have been launched into webby using HTML pages and class files of the applets. A Google form based interactive portal has alsobeen launched that helps users to interact with developers directly. Users can access the developedexperiments at the following link: https://www.ee.iitb.ac.in/course/~vel/

Keywords—Electromagnetic field theory; Java Applets; Virtual labs; Finite Element Method; Methodof Moment

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https://www.ee.iitb.ac.in/course/%7Evel/

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Biography

Dr. S. V. Kulkarni is Professor in the Department of Electrical Engineering, Indian Institute of Technology Bombay,India. Previously, he worked at Crompton Greaves Limited (1990-2001) and specialized in the design anddevelopment of transformers up to 400 kV class. He was a recipient of the Young Engineer Award conferred by theIndian National Academy of Engineering in 2000 for his contributions to Electromagnetic Field Computations andHigh Voltage Insulation Design in transformers. He was also honoured with the Career Award for Young Teachersfrom All India Council for Technical Education in 2001. He received Best Paper Awards in international conferenceson transformers held in 2002 and 2006.He has authored a book Transformer Engineering: Design, Technology, and Diagnostics, Second Edition, publishedby CRC Press in September 2012. The first edition published in 2004 received an overwhelming response worldwide.He has also written a chapter Challenges and Strategies in Transformer Design in the book Transformers: Analysis,Design, and Measurement published by CRC Press in June 2012. He has also adapted an undergraduate textbook onelectromagnetics for Asia, Principles of Electromagnetics, Oxford University Press, published in October 2015.His extensive interactions with transformer and power industries are reflected in his numerous consultancy projects forthem. He has organized several training programs on transformers and computational electromagnetics for engineersfrom industries and academia in India. He has also set up the Field Computation Laboratory and the InsulationDiagnostics Laboratory in the Electrical Engineering Department at IIT Bombay.He has more than 150 publications to his credit in reputed journals and conferences. He has one US patent ontransformer deformation diagnostics. He is a Fellow of the Indian National Academy of Engineering. He is also anEditor of IEEE Transactions on Power Delivery. His current areas of research include Analysis and Diagnostics ofPower Transformers, Advanced Electromagnetic and Coupled Field Computations, and Distributed Generation andSmart Grids.For more details, see: http://www.ee.iitb.ac.in/wiki/faculty:svk

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Outline Issues and challenges in teaching electromagnetics

Important concepts that need to be elaborated

Ways of effective teaching

Web based virtual laboratory

Some sample experiments

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Issues and Challenges in Teaching Electromagnetics The course is comparatively abstract as compared to circuits-

based courses

The subject should not be taught as a mathematical course

“Physics” and “What is happening in space” need to beexplained

General feeling in academia: “Students find it difficult to understand and pass the subject” “Teachers do not like to teach the subject”

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Important Concepts that Need to be Elaborated Divergence and Curl

Divergence of a vector (Gauss’s law in Maxwell’s equation)

Many students are not clear whether ρv is free charge density or boundcharge density?

Curl of a vector (Ampere’s law in Maxwell’s equation)

Does the curl of the magnetic field produced by a current carryingconductor remain same in the inner and outer regions of the conductor?

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vρ∇ ⋅ =D

∇× =H J

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Continuity equation and displacement current density

How the above equation can be related to Kirchhoff's Current Law,particularly to currents in a circuit consisting of R, L and C elements?

εr and μr Understanding the two as complex numbers

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v

tρ∂

∇ ⋅ = −∂

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Coulomb's and Lorentz gauge Understanding that Coulomb's gauge is a special case of Lorentz gauge

Electric length and transient time at high frequencies

Free space impedance – a pure resistance

Radiation at high frequencies: visualization

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Vt

µε ∂∇ ⋅ = −∂

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Ways of Effective Teaching Appropriate mix of theory and practical examples involving

real life equipment and systems

Emphasis on “spatial distribution” of fields rather than thegoverning math

Creating a common set of presentations

Inclusion of numerical techniques (FEM, MoM) into thecourse

Interactive web based teaching techniques

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Web Based Laboratory One of the main difficulties in learning electromagnetics is

visualization of fields Field distributions in different practical devices are governed

by partial differential equations, and it is very difficult to solvethem analytically

Numerical techniques like Finite Element Method (FEM) andMethod of Moments (MoM) can be used to solve thesegoverning differential equations, but these are not easilyaccessible to or understood by students

This web based lab uses FEM and MoM results to explainbasic concepts

Applications have been built by using Java based applets,which are deployed into web by using HTML

11Ref: https://www.ee.iitb.ac.in/course/~vel/

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Java applets Interactive features for the web based lab are provided by Java applets,

which may not be provided by HTML alone. Features like check boxes, buttons, and user actions with mouse can be

incorporated/captured Applets can change field plots in response to the user selection This makes applets well suitable for demonstration, visualization, and

teaching

To run these Java applet based experiments on a personalcomputer, Java environment is needed to be configured

For this, the user needs to install the latest version of JDK(Java Development Kit), and JRE (Java Runtimeenvironment): open source software

After installing these software, security issues have to becleared by adding the website link to the exception site list inthe Java control panel

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Main Features of the Web Based Lab Experiments in the lab are designed using FEM/MoM and

Matlab based analytical results of familiar practical applications Users can change the parameters assigned in each experiment

and can visualize how the fields depend on these parameters A google form based interactive portal has been launched so that

users can directly give feedback to the developers It is very easy to create Java environment in a personal

computer: open source software and one time installation Experiments have been chosen in accordance with

undergraduate curricula

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bay Curl of a Vector

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Electron Movement in Different Media

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Electron moving in a dielectric

Electron moving in a metal

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Eddy Currents and Skin Effect

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Flux penetration

Variation of field

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Direction of Fields in a Rectangular Waveguide

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Antenna Radiation

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Current distribution Radiation field

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References

Matthew N.O. Sadiku and S.V. Kulkarni, Principles of Electromagnetics. Sixth Edition, AsianAdaptation, New Delhi, Oxford University Press, India, September, 2015, 908 pages, (Asianadaptation of the original text book: Matthew N.O. Sadiku, Elements of Electromagnetics, SixthInternational Edition, Oxford University Press)

M. F. Iskander, “Technology-based electromagnetic education,” IEEE Transactions on Education,Vol. 50, No. 3, pp. 1015-1020, Mar. 2002.

K. Preis, I. Bardi, O. Biro, R. Hoschek, M. Mayr, and I. Ticar, “A virtual electromagnetic laboratoryfor the classroom and the WWW,” IEEE Transactions on Mangetics, Vol. 33, No. 2, pp. 1990-1993, Mar.1997.

M. Munoz, “Using graphical based software to aid in the understanding of electromagnetic fieldtheory,” in Froniters in Education Conference , Vol. 2, pp. 863-867, Aug. 1996.

V. Pulijala, A. R. Akula, and A. Syed, “A web-based virtual laboratory for electromagnetic theory,”in Fifth International Conference on Technology for Education, pp. 13-18, 2013.

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Thank you

A virtual interactive electromagnetic laboratory:�an effective pedagogical approach��CopyrightAbstractBiographyOutlineIssues and Challenges in Teaching Electromagnetics�Important Concepts that Need to be Elaborated�Slide Number 8Slide Number 9Ways of Effective TeachingWeb Based LaboratorySlide Number 12Main Features of the Web Based LabCurl of a VectorElectron Movement in Different MediaEddy Currents and Skin EffectDirection of Fields in a Rectangular WaveguideAntenna Radiation References�Slide Number 20