# 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

11685

6.0

##### Responsible teacher

Pedro Miguel Ribeiro Pereira

Weekly - 4

Total - 55

Português

### Prerequisites

Knowledge adequate to the level of study, namely:

• Fundamentals of electromagnetism
• 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 support materials.The team work is encouraged. The oral communication is stimulated.

### Evaluation method

The evaluation method could be one of the following:

a) 2 Tests (MT) + Laboratoty Work (TL)

Classification of (MT) = (0,40*MT1+0,60*MT2) >= 9,5 val. and TL >= 9,5 val.

### Final Classification  = 0,80*C(MT) + 0,20*TL >= 9,5 val.

b) Final Exam (Ex) +  Laboratoty Work (TL)

Final Classification = 0,80*(Ex. Classification >= 9,5 val.) + 0,20*TL >=9,5 val.

TL, whose classification must be greater than or equal to 9.5 and is mandatory for obtaining frequency

## 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. Synchronous machine (or, alternator)

1. Constitution and operation principles of synchronous generator

2. Equivalent electrical circuit of the generator

3. The generator working in an isolated grid

4. Parallel connection of synchronous generator

5. Salient pole synchronous generator: main characteristics and applications

## Programs

Programs where the course is taught: