Environmental Engineering

Introduction to electric circuits Basic circuit elements. Passive and active sign convention. Ideal current and e.m.f. sources. I-V characteristics of basic circuit elements. Real sources and their I-V characteristics. Direct current networks Kirchhoff’s circuit laws. Equivalent resistance. Superposition principle. Network theorems (Thevenin, maximum power transfer, etc.). Mesh current method. Node voltage method. Alternating current networks Phasors. I-V characteristics of basic circuit elements in AC. Series and parallel resonance. AC powers. Network analysis theorems in AC. Node voltage method. Power factor correction. Network analysis in the presence of mutual inductances. Three-phase systems Balanced three phase systems. Equivalent one-phase circuit. Unbalanced three phase systems. Power in three phase systems. Power factor correction of a three phase load. Transformers Ideal transformer and equivalent circuit. Physical structure. Equivalent circuit of the real transformer. Introduction to the three-phase transformer. The induction motor Electromechanical energy conversion. The rotating magnetic field. The induction motor. Operating principle. Physical structure of the induction motor. Equivalent one-phase circuit. Power and torque. Mechanical characteristic and torque speed-curve. Motor starting issues. The synchronous generator Operating principles. Physical structure. Equivalent one-phase circuit. Armature reaction. No load and on-load operation. Power and torque. Applications Introduction to Electrical power systems General considerations over the production, transmission and distribution of electrical energy. Voltage drops. Overvoltages and overcurrents. Distribution networks. Ground connections. IT, TT, TN systems. Electrical safety issues

Complex numbers, Electrostatics, Magnetostatics, Linear Algebra: Matrices, The current density field

-Elettrotecnica, volume II, Marcello D'Amore, Ed. Siderea; -Elettrotecnica e applicazioni, Liguori Editore, Giulio Fabricatore, Liguori Editore; -Principi ed applicazioni di elettrotecnica, volume II, Guarnieri-Stella, Edizioni progetto Padova. - Elettrotecnica Vol I (Principi) e II (Applicazioni), G.Chitarin, F.Gnesotto, M.Guarnieri, A.Maschio, A.Stella. Società editrice Esculapio.

Non mandatory face to face lectures, though strongly encouraged

Evaluation consists of a written exam, divided into two parts: the first part, lasting 90 min, consists in the solution of a typical engineering problem, namely an electrical circuit in the periodic sinusoidal regime, aimed at verifying the students’ ability in combining theoretical concepts with a classical practical problem, concerning electrical networks in AC. The second part, lasting 60 min, consists of two open questions over the entire course programme. The final score is the average of the scores of both parts. Oral examination is on a voluntary basis.

The course involves face to face lessons, along with weakly sessions with numerical examples on both DC and AC circuits