Electrotechnics

Basic notions of physics and mathematics.

The subjects are essentially exposed in theoretical lessons, complemented by the presentation, at theoretical-practical lessons, of electrical applicative models and systems.
In the theoretical-practical lessons, exercises are solved and assemblies of electrical schemes and instrumentation for electrical quantities measurement are presented.

The main objective of this course unit is to acquire knowledge in terms of the main electrical parameters and their measurement, so that students can understand the technical language, interpret the technical data of electrical equipment, make the connection between electrical power and electromechanical devices, analyze electrical circuits and know how to use instrumentation to measure electrical parameters.

Introduction and definitions.

Direct current.

Association of sources and receivers. Main analysis circuits laws and theorems. Series, parallel and both configuration circuits.

Alternative current.

Alternating current effects. Sinusoidal single-phase alternative current. Mean and root mean square electric values. Mathematical and vectorial representation. Circuits R, L, C. Reactance and Impedance. Circuits RL, RC, RLC series and parallel. Resonance. True, reactive and total electric power. Power factor compensation.

Three-phase systems.

Simple and composed voltages. Wye and delta connections. Three phase currents. Three-phase Powers. Power factor compensation.

Electric motors.

Motors classification. Main characteristics and field of application of the several types of motors. Outburst types. Direct and pull wye-delta outburst.

Bases of Project of electrical distribution systems.

Electric cables. Command, regulative and protective devices.

Students will be able to choose one of the following assessment methods:

  1. Assessment by exam:

         a. Written test rated at 20 points to be taken during official exams dates.

  2. Periodic assessment:
         a. Carrying out two assessment tests, with dates defined by the Course Committee: 

                    Test1 - 10/20 points (from the 8th week);
                    Test2 - 10/20 points (on the 1st exam date).

        b. Criteria:

           - Mandatory minimum attendance of 75% in all classes type, until the date of each test; (students from previous academic years are exempt from this criterion)
           - A minimum grade of 35% is required in each test.
           - The average of the 2 tests must be equal to or greater than 9.5/20 points;

 All written tests (test or exams) include two components, a theoretical component and a theoretical-practical component, corresponding to 25% and 75% of the grade, respectively.

Regulation for query elements:
     • In the theoretical part of the written tests or exams, elements consultation or the use of equipment are not allowed.
     • In the theoretical-practical part of the tests or exams, only the use of a scientific calculating machine and the consultation of the form provided by the teacher are allowed.

IMPORTANT NOTES:
• In the periodic assessment, if the minimum attendance criterion is not met or the minimum grade criterion is not met in any of the tests, regardless of the grade obtained, the student will have to undergo to a global exam for 20 points;
• The grade from the 1st test will only be considered in the 1st exam, in the other exams calls the student will have to undergo to a full exam for 20 points.

NAO