# 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

12513

3.0

##### Responsible teacher

Nuno Manuel Gonçalves Vilhena

Weekly - 3

Total - 46

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

• John Bird, Electrical Circuit Theory and Technology 2nd Ed, Newnes, 2003.
• Nassir H. Sabah, Electric Circuits and Signals, 1st Ed., CRC Press, 2008, ISBN 9781315219868
• Meizhong Wang, Understandable Electric Circuits, 1st Ed., The Institution of Engineering and Technology, 2010, ISBN 978-1-84919-114-2 (PDF)
• Documentation provided by the professor.

### Teaching method

The distinct concepts, techniques and theories are explained by the professor 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

EVALUATION RULES

GENERAL ELECTRICAL ENGINEERING (EG) 2023/2024

# CONTINUOUS EVALUATION, EXAMINATION AND FINAL CLASSIFICATION

The evaluation method could be one of the following:

a)       1 Test (T ) and 2 Practical Works (PW1 + PW2)

T ≥ 9.5 values

PW = 0,50*PW1 + 0,50*PW2 ≥ 9,5 valores

Where T is the final classification for the theoretical component, TP is the final classification for the practical component and FG is the final grade obtained using the following equation:

FG = 0.70*T + 0.30*PW ≥ 9.5 values

b)      Final Exam (Ex) and a 2 Practical Works (PW1 + PW2)

Exam classification (Ex) ≥ 9.5 values

Where FG is the final grade, obtained using the following equation:

FG = 0.70*Ex + 0.30*PW ≥ 9.5 values

# APPROVAL TO THE CURRICULAR UNIT

In both cases, to be approved, student must have a final grade equal or greater than 9.5 values (in a 0 to 20 scale), and both classification components (T) and (PW) also equal or greater than 9.5 values (in a 0 to 20 scale).

# FINAL NOTES

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

Students with practical component already concluded and approved in 2022/2023 will be dismissed of doing it again if they wish. In any case, students must inform the professor about their decision: if they want to keep the previous mark or to repeat the laboratory component.

The regulation was elaborated in accordance with the norms established in the FCT NOVA evaluation regulation available here.

## Subject matter

CURRICULAR UNIT PROGRAM

GENERAL ELECTRICAL ENGINEERING (EG) 2021/2022

# 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

1. Definition of a three-phase voltage system
2. Delta and Star (with/without neutral conductor) connections
4. Three-phase electric power

# 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: