28633 - Electrotechnics T-A (L-Z)

Learning outcomes

At the end of the lessons, the Student will know the main aspects of the use of electrical energy as: operating principle and characteristics of three phase systems, transformers,generators, motors andprotection apparatus.

Course contents

Prerequisites: the student should understand the main concepts of analysis and physics as presented in the courses of the first year of the School of Engineering. In particular: solution of ordinary differential equations, operations with complex numbers, partial differential equations, electromagnetic field equations in the vacuum space

Program:

Electric circuits. From field theory to circuit theory. Lumped parameter electric circuit. Kirchhoff's laws. Main circuit devices: resistor, inductor, capacitor, ideal voltage and current source, diode. Main network analysis methods:fundamental loops, node voltages, series and parallel connection of resistors. Main theorems for linear network analysis: superposition principle, Thevenin, Norton. Introduction to network analysis in transient regime. Alternate current regime. AC network analysis with the phasor method. Electrical power in AC regime. Reactive power compensation. Three-phase systems. Star and delta connected loads. Power in three-phase systems. Three-phase systems with neutral wire.

Transformer. Main characteristics and operating principle. Equivalent electrical network. No load and short circuit operating regime. Efficiency measurements. Three phase transformers. Parallel connection of transformers.

Asynchronous machines. Main characteristics and operating principle. Rotating magnetic field. Equivalence theorem and equivalent electric network. Mechanical and electro-mechanical characteristics.

Synchronous machines. Main characteristics and operating principle as generator and compensator.

Direct current machines. Main characteristics and operating principle as motor and generator.

Electric power systems and electrical safety. Electric power generation, transmission and distribution. Protection against unintended connections. Protections against over-currents and over-voltages.

Readings/Bibliography

The student can find a treatise of the topics analyzed during the course in the following books and can utilize a trace of the lessons which is online on the website of the teacher (http://www.die.ing.unibo.it/pers/ribani/ribani.htm)

G. Chitarin, F. Gnesotto, M. Guarnieri, A. maschio, A. Stella, "Elettrotecnica: 1 - Principi", "Elettrotecnica: 2 - Applicazioni", Esculapio, 2018

G. Rizzoni, "Elettrotecnica: principi e applicazioni", McGraw-Hill, 3 edizione, 2013.

A. R. Hambley: "Elettrotecnica", Prentice Hall, 4 edizione, 2013

Teaching methods

The course is carried out with classroom lessons during which all the topics of the program are developed. In particular the electric circuit topics are treated writing on the blackboard giving a lot of space to exercises on the numerical solution of linear electric circuits in dc and ac regime, of monophase and threephase type. The topics regarding the electrical machines and the electrical safety are developed mainly with computer presentations which are online at the website of the teacher.

Assessment methods

The examination is made of a written and of an oral test. The written test verifies the knowledge of the circuit theory and consists in the solution of a linear electric circuit, of the monophase or threephase type, in alternate current regime. During the test, the student can not check any written document but needs to use a scientific calculator. The grade of the test will be in thirtieth; the grade of the test is obtained subtracting to the maximum grade (30 for a correct solution, either for the procedure and the numerical values) 5 points for any conceptual mistake and 1 point for any calculation mistake. The test is passed when the grade is larger than or equal to 15/30. The oral test can be attended only after the positive result of the written test. During the oral test the student presents two of the topics of electrical machines, electrical power systems and electrical safety part of the program, chosen by the teacher.  The final grade is obtained by the average value of the grades of the two tests, adding or subtracting up to two points whether the grade of the oral test is larger or lower of the grade of the written test.

Links to further information

http://www.die.ing.unibo.it/pers/ribani/ribani.htm

Office hours

See the website of Pier Luigi Ribani