Electrotechnics and Electrical Machinery
Objectives
The students should acquire mathematical and physical foundations of applied electrotechnics, namely, of the electric power’s production, distribution and use, and should also obtain solid knowledge concerning composition and characteristics of the most relevant electrical machines used in energy systems.
General characterization
Code
11685
Credits
6.0
Responsible teacher
João Francisco Alves Martins
Hours
Weekly - 4
Total - 55
Teaching language
Português
Prerequisites
Knowledge adequate to the level of study, namely:
- Fundamentals of electromagnetism (electrical charge, current and voltage).
- Complex numbers.
- Differential and integral calculus.
Bibliography
- C. Alexander and M. Sadiku, Fundamentals of Electric Circuits, Mc-Graw Hill, 2nd Ed., 2002
- Vítor Meireles, Circuitos Eléctricos 6ª Edição, LIDEL, 2010.
- John Bird, Electrical Circuit Theory and Technology 2nd Ed, Newnes, 2003.
- Stephen J. Chapman, Electric Machinery Fundamentals, McGraw-Hill (5th ed., 2012)
- George McPherson & Robert D. Laramore, An Introduction to Electric Machines and Transformers, Wiley (1990)
- PPT presentations provided by CU teacher.
- Documentation provided by the lecturer.
Teaching method
The distinct concepts, techniques and theories are explained by the lecturer with the support of slides and practical demonstrations with different equipments.
Students assess their skills through semiautonomous resolution of sets of problems, available in the support materials. The team work is encouraged. The oral communication is stimulated.
Evaluation method
Students are assessed through three examinations (35% + 35% + 30%).
The exam will consist of three modules, each one equivalent to each of the tests. If the student chooses to be evaluated by exam, the following rule will apply: each module delivered at the exam replaces the grade of the respective test (even if the grade of that exammodule is lower than the respective test), and for each module not delivered (in the exam) the grade of the respective test will be considered. The percentage breakdown of the modules is the same as the tests.
Subject matter
CURRICULAR UNIT PROGRAM
Electrotechnics and Electrical Machinery (EME) 2024/2025
I. Direct current circuits analysis
- Eletric resistence, power and energy (a review)
- Kirchoff laws
II. Alternate current circuit analysis
- Inductors and capacitors
- Average value and RMS value of a time variable signal
- Complex amplitude and fasors
- RL, RC and RLC circuits
- Power
- Power factor correction in an industrial power plant
III. Triphasic circuits analysis
- Definition of a three-phase voltage system
- Delta and Star (with/without neutral conductor) connections
- Balanced and unbalanced loads
- Three-phase electric power
IV. Transformers
- Principle of operation
- General equations
- Equivalent eletrical circuit for ideal and real transformer
- Applications
V. Assynchronous machine (or, induction machine)
- Constitution and operation principles as motor and generator
- Induction motor: mechanical speed, torque, power and efficiency
- Equivalent electrical circuit of the motor
- Speed control processes
- Applications
VI. Synchronous machine (or, alternator)
- Constitution and operation principles of synchronous generator
- Equivalent electrical circuit of the generator
- The generator working in an isolated grid
- Parallel connection of synchronous generator
- Salient pole synchronous generator: main characteristics and applications