# General Electrical Engineering

## Objectives

The students, through rigorous scientific deduction, should become aware of the mathematical and physical foundations of applied electrotechnics, namely, of the electric power’s production, distribution and use, and of the composition and characteristics of the most relevant industrial electrical machines.

On the other hand, students must become competent to model, analyse and calculate simple electric power circuits and networks, including balanced three-phase ones. Students will become able to make technically based choices of simple electrical equipments.

Other important objective is the development of oral communication and team work among students, using adequate procedures in theoretical and practical classes.

## General characterization

11054

6.0

##### Responsible teacher

Anabela Monteiro Gonçalves Pronto

Weekly - 4

Total - 60

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

Vítor Meireles, Circuitos Eléctricos 6ª Edição, LIDEL, 2010.

John Bird, Electrical Circuit Theory and Technology 2nd Ed, Newnes, 2003.

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 slides.

### Evaluation method

The evaluation method could be one of the following:

a) 2 Tests (MT) and a practical work (TP)

C(MT)= 0,35*MT1 + 0,65*MT2 ≥ 9,5 valores

e

TP ≥ 9,5 valores

The final classification FC is obtained using the following equation:

FC = 0,80*MT + 0,20*TP ≥ 9,5 valores

### b) Final Exam (Ex) and a Practical Work (TP)

Exam classification ≥ 9,5 valores

FC = 0,80*Ex. + 0,20*TP ≥ 9,5 valores

In both cases, to be approved, student must have a final classification equal or greater then 9.5 values (in a 0 to 20 scale), and both classification components (MT) and (TP) also equal or greater than 9,5 values (in a 0 to 20 scale).

If necessary, the teacher responsible for the subject can require an oral exam to evaluate (or, re-evaluate) the theoretical and/or the practical component of the subject.

## Subject matter

I. Direct current circuits analysis

1. Eletric resistence, power and energy (a review)

2. Kirchoff laws

II. Alternate current circuit analysis

1. Inductors and capacitors

2. Average value and RMS value of a time variable signal

3. Complex amplitude and fasors

4. RL, RC and RLC circuits

5. Power

6. Power factor correction in an industrial power plant

III. Triphasic circuits analysis

IV. Transformers

1. Principle of operation

2. General equations

3. Equivalent eletrical circuit for ideal and real transformer

4. Applications

V. Assynchronous machine (or, induction machine)

1. Constitution and operation principles as motor and generator

2. Induction motor: mechanical speed, torque, power and efficiency

3. Equivalent electrical circuit of the motor

4. Speed control processes

5. Applications

VI. Energy efficiency and audit

1. Energy efficiency definition
2. Legal framework
3. Electrical energy audit

## Programs

Programs where the course is taught: