28633 - Electrotechnics T-A (A-K)

Learning outcomes

Expand and develope of concepts and methodologies relating steady state and quasi steady state electromagnetism. Provide the main tools for the analysis of electric and magnetic circuits. Illustration of the construction and operation of the main electrical machinery and components of an electric power system.

Course contents

Requirements/Prior knowledge

A basic knowledge of electromagnetisms is requires. This knowledge is usually acquired passing the exam of Physics T-B. The student should also have gained a good knowledge of the fundamentals of differential and integral calculation, provided in the Mathematical Analysis courses.

All lectures will be held in Italian. It is therefore necessary to understand the Italian language to successfully attend the course and to be able to use the educational material provided.

 

Course Contents

Electromagnetic Fields
Recalls on the main vector operators. Basic definitions. Maxwell's equations in differential and integral form. From field theory to the theory of circuits.

Electric Circuits
Lumped circuits and networks. Read Kirkhhoff. Main circuit elements: resistors, inductors, capacitors, independent voltage and current. Steady state. Series and parallel of resistors. Transformations delta - wye. Methods of study of electrical circuits. Kirkohhoff method of equations. Method of node potentials. Mesh method. Superposition. Tellegen's theorem. Thevenin and Norton's theorems. Studies on transients in RC, LC, RLC circuits. Initial state of the components. Sinusoidal steady state. Symbolic Kirkhhoff laws. The concept of impedance. Analysis of circuits in sinusoidal regime using the symbolic method. Power in sinusoidal regime. Power factor. Three phase systems. Wye and delta loads. Balanced and unbalanced Loads. Power absorbed by a three-phase load. Three phase with neutral.

Magnetostatics
Magnetic properties of materials. Diamagnetic, paramagnetic and ferromagnetic materials. magnetic circuits. Self and mutual inductance coefficients

Principles of electromechanical energy conversion
Energy balances in electromechanical systems. Calculation of forces and torques in mechanical systems.

Electrical machines
General. Magnetic circuits. Hopkinson's law. Loss phenomena in electrical machines. Rotating magnetic field.

The transformer. Operational principle. Field hypothesis. Internal and external equations. Equivalent circuits. No-load and short circuit conditions. Efficiency measurement .

Asynchronous machines. Operational principle. Field hypothesis. Internal and external equations. Equivalence theorem. Mechanical and electromechanical curves.

Synchronous machines. Operational principle. Internal and external equations.

Electrical power systems

General information on electrical systems and their constitution. Power plants and energy sources, power lines, switchgear and protective devices, basic electrical safety grounding system

Readings/Bibliography

The teaching material necessary in order to follow the course is available from AMS Campus - AlmaDL - University of Bologna. Username and password are reserved for students enrolled at the University of Bologna.
For further reading, we recommend the following books:

G. Rizzoni, 'Principles and applications of Electrical Engineering', Mc Graw Hill

C. Alexander, M. Sadiku, 'Electrical circuits', Mc Graw Hill

P. Ghigi, M. Martelli, F. Mastri 'Esercizi di Elettrotecnica', Ed. Pitagora

Teaching methods

The course takes place on the first cycle of the second year of the degree course in "Ingegneria Gestionale", and consists of 6 credits corresponding to 60 hours of lectures, during which the teacher will explain in classroom the topics covered in the program. About 40 hours will be devoted to the theoretical development of the fundamental concepts and methodologies of electrical engineering. The remaining 20 hours will be devoted to exercises, during which the student, using the theoretical notions developed, will acquire the practical skills necessary to analyze electrical circuits in steady state, transient and sinusoidal regime, as well as three-phase systems and magnetic configurations.

Assessment methods

The exam is aimed to assess the acquisition by the student of the basic concepts in electrical engineering.

During the examination the student must demonstrate the knowledge of the fundamentals which enable to apply the electromagnetic theory to the study of the most common applications of electrical engineering (electrical circuits, electric power systems, electric machines).

The student must also demonstrate his ability in solving independently simple illustrative problems, applying the methods developed during the course.

The student can pass the exam by using one of the following ways:

Partial tests: the student will take two partial tests, the first one at the middle of the course, and the second one at the course end. During each test a question, regarding one of the topics covered in class, and two exercises will be administered to the students.

The student will have 20 minutes to answer the question, producing a short written text, where he will be expected to demonstrate the achievement of a comprehensive vision of the proposed theme, the mastery of specific technical language and his ability to synthesis and analysis.

The student will then have 120 minutes to solve the two proposed exercises. During the first partial test, the exercises will focus on the study of electrical circuits in steady state and transient regimes. The exercises of the second partial test will instead focus on the study of circuits in sinusoidal regime, three-phase systems and magnetic circuits. The student must demonstrate to know how to properly apply the analytical methods developed during the course and to have acquired a critical sensitivity to the results obtained.

At the end of the two partial tests two average scores will be issued, one for the exercises and one for the answers to the questions. The exam is passed if both scores are above sufficiency.

Comprehensive examination: students can enroll in one of the exams published on the AlmaEsami system. The comprehensive examination consists of a written and an oral test. The written test consists of two exercises, aimed to verify that the student is able to correctly apply the analysis methods developed during the course and that he has acquired a critical sensitivity to the obtained results. The student will have 120 minutes to solve the exercises, which will focus on the study of electrical circuits in transient and sinusoidal regimes, three-phase systems and magnetic circuits.

A minimum score of 14/30 is required to the student in order to access the oral exam phase.

During the oral examination, the student will be invited to discuss some of the topics taught during the course. The discussion will be aimed at confirming that the student has reached an organic view of the proposed topic, that he has achieved a good grasp of the specific technical language and has acquired capacity for synthesis and analysis.

The degree of satisfaction of the above mentioned requirements will contribute to the formulation of the final score, together with the mark obtained in the written test.

Teaching tools

Handouts, information and other course material is distributed through the web site: http://campus.unibo.it/

Links to further information

http://www.die.ing.unibo.it/pers/cristofo/andrea.htm

Office hours

See the website of Andrea Cristofolini