06793 - Electrotechnics

Learning outcomes

At the end of the course, the student will have knowledge of the fundamental properties of electrical circuits, the main methodologies of circuit analysis, the basic principles on which the transmission and distribution of electrical energy are based, magnetic circuits, the basic laws of electrical machines and the operating principles of the transformer.

Course contents

Definition of fundamental quantities and laws

Definition of circuit theory and electrical circuit, the definition of voltage, current, power, and energy. Kirchhoff's laws. Basic circuit elements: resistor and idea sources. Ohm's law.

Direct current circuits

Analysis of resistive circuits with one generator. Series and parallel connection, voltage divider and current divider. Solution of circuits by simplification. Circuit properties and methods of analysis: superposition of effects, Millman's theorem, Thevenin's and Norton's theorems, nodal analysis. Principle of maximum power transfer

Transients

Introduction to transient circuits, the definition of basic circuit elements: capacitor, inductor. First-order circuits. Study of first-order transients RL and RC using equations of state

Sinusoidal steady-state

Definition of sinusoidal steady-state, periodic quantities, sinusoidal quantities, operations between isofrequential sinusoidal quantities. Symbolic method: phasors. Operations with phasors: a reminder of the algebra of complex numbers; properties of phasors. Kirchhoff's laws in symbolic form, constitutive laws of electrical components in symbolic form: impedance and generalized Ohm's law. The generalization of principles and theorems in the phasor domain, phasor diagram.

Power in sinusoidal steady-state circuits: instantaneous power, active and reactive power, complex and apparent power. Maximum power transfer in sinusoidal steady-state. Boucherot's theorem Power factor correction of single-phase ohmic-inductive loads.

Three-phase circuits

Origins of three-phase systems. Definitions: symmetrical system, balanced system, phase voltages, line-to-line voltages, three-wire system, four-wire system. Star connection and delta connection; three-phase loads in series and parallel. Equivalent single-phase circuit. Three-phase power factor correction: star and delta connection of power factor correction capacitors. Connection of single-phase loads.

Magnetic circuits

Diamagnetic, paramagnetic and ferromagnetic materials. Magnetic circuits with lumped parameters; Hopkinson's law. Hysteresis. Definition of hard and soft ferromagnetic materials. Application: differential switch

The transformer

Principle of operation of single-phase transformer; ideal transformer; hysteresis and eddy current losses; transformer equivalent circuit.; standard tests; three-phase transformer.

Elements of electrical systems

Scheme of the electrical system. Comparison of single and three-phase alternating current transmission lines. Protection against electrical contacts: differential relay.

Readings/Bibliography

Suggested books:

• “Elettrotecnica: elementi di teoria ed esercizi”, M. Repetto e S. Leva, Città studi edizioni
  
• “Electric circuits”, Charles K. Alexander, Matthew N. O. Sadiku, McGraw-Hill Education
• "Circuiti Elettrici" di Renzo Perfetti, Zanichelli

Teaching methods

The course consists of lectures and exercises. Handouts and compendium material will be provided by the lecturer and uploaded on the course webpage

Assessment methods

Learning outcomes are assessed through a final exam that evaluates the acquisition of the expected knowledge and skills via a written test lasting approximately 2 hours.

The written exam consists of a series of multiple-choice questions and two exercises in which students are required to analyze electrical circuits.

Students will pass the exam if they demonstrate mastery and practical application of the key concepts covered in the course, particularly the fundamental concepts of circuit theory and the ability to solve electrical and magnetic circuits. A higher score will be awarded to students who are able to apply and integrate all course content. Failure to pass the exam may be due to insufficient understanding of key concepts.

In accordance with the University Code of Ethics (Codice Etico di Ateneo), students’ attention is drawn to the obligation to adopt conduct based on the highest standards of integrity.
Any activity that may compromise the proper conduct of examinations is prohibited, including but not limited to:

• cheating and plagiarism;
• access to online learning resources;
• use of artificial intelligence tools not expressly authorized;
• use or possession of unauthorized materials or equipment.

It is specified that the mere possession of unauthorized tools or materials during the conduct of any examination results in the immediate invalidation of the submitted work and notification to the competent offices.

Any conduct in violation of the above provisions may result in disciplinary proceedings and, where criminal relevance applies, reports to the competent authorities, with the consequent risk of criminal proceedings being initiated against the students involved.

Teaching tools

As a useful tool for learning and testing exercises, the use of the SpicePyBot tool on Telegram is proposed.

Documentation of the tool can be accessed at the following link:

https://github.com/giaccone/SpicePyBot

Office hours

See the website of Vincenzo Cirimele