06793 - Electrotechnics

Academic Year 2024/2025

  • Teaching Mode: Traditional lectures
  • Campus: Forli
  • Corso: First cycle degree programme (L) in Mechanical Engineering (cod. 0949)

    Also valid for First cycle degree programme (L) in Aerospace Engineering (cod. 9234)

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

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

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

SDGs

Affordable and clean energy Sustainable cities Responsible consumption and production

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.