Electrical Machines and Electricity

Recommended Prerequisites

Physics II, Linear Algebra

Teaching Methods

Classes take place in theoretical and practical scheme in which theoretical concepts are illustrated with examples. The theoretical modules are expository in nature tutorial, using multimedia. The practical classes will be used to develop, illustrate and settle deeper into the application in practical problems, the theoretical and methodological concepts presented in lectures. Can be suggested to students to carry out work of a seminar, or experimental work on selected topics of the syllabus.

Learning Outcomes

Analysis and characterization of AC single and three phase circuits. Understanding Electrical power in AC systems, power factor and power factor compensation. Undestanding the magnetics phenomena that suporting the working principle of the electrical machinery. Description and analysis of the working principle of the transformers, synchronous generators, synchronous motors, induction motors and drives. The student should be able to describe and predict operation point of a motor, to choose the correct motor according to an industrial task, and evaluate the energy consumption of an electric machine.

The aim is the development of instrumental skills (oral and written communication), personal (critical thinking) and systemic (apply in practice the theoretical knowledge).

Work Placement(s)

No

Syllabus

Single-phase circuits with resistors, inductors and capacitors, impedance and impedance associations. Notion of instantaneous power, apparent power, real and reactive power, power factor compensation. Basic three-phase circuits, delta connection and star with and without neutral. Magnetic field and magnetic induction. Magnetic circuits, fundamental equations, flux, magnetomotive force and reluctance. Working principle of the transformer, voltage regulation and efficiency. Principle of operation of the rotary electric machine such as a generator and motor. Three Phase Synchronous Motor and Generator - construction, working principle, equations, and operating characteristics, starting, regulating the power factor. Three-phase Induction Motor - construction, working principle, slip and speed, operating characteristics, start-up procedures, engine rotor cage or short-circuited, wound-rotor motor or rings. Variation of speed. Motor selection based on load curve.

Head Lecturer(s)

Ricardo António Lopes Mendes

Assessment Methods

Assessment
Synthesis work: 20.0%
Exam: 80.0%

Bibliography

- Nilson, James W., Electric Circuits, Addison Wesley Pub. 10th Ed., 2015.

- Charles Alexander and Matthew Sadiku, Fundamentals of Electric Circuits 7th Edition, 2020

- Meireles, Vitor Cancela; Circuitos Eléctricos, LIDEL, 5ª ed. 2009.

- Chapman, S., Electric Machinery Fundamentals, Mc Graw Hill, 5th ed., 2011.

- Mendes, Ricardo, PDF’s de apoio às aulas teóricas, 2018.