Educational guide 2020_21
Centro Universitario da Defensa na Escola Naval Militar de Marín (Pontevedra)
Grao en Enxeñaría Mecánica
 Subjects
  Fundamentals of electrical engineering
   Contents
Topic Sub-topic
Unit 1. Direct current circuits This topic aims to study the techniques of analysis and resolution of basic DC circuits.

1.1 Introduction and general concepts. Common measurement units.
1.2 Electrical circuit. Elementary components.
1.3 Kirchhoff's Laws.
1.4 Voltage and current sources. Font conversion.
1.5 Voltage and current dividers.
1.6 Serial and parallel association.
1.7 Analysis of circuits by nodes and meshes.
1.8 Theorems of Thévenin and Norton.
Unit 2. Alternating current circuits The objective of this topic is to study the techniques of analysis and resolution of basic alternating current circuits.

2.1 Periodic waveforms and associated parameters.
2.2 Phasorial representation.
2.3 Impedance and admittance concept. Elements of the circuit: Resistance, Capacitor and Inductor.
2.4 Active, reactive and apparent power. Triangle of powers. Power factor
2.5 Analysis of alternating circuits
Unit 3. Three-phase current circuits This topic aims to study the techniques of analysis and resolution of basic circuits in three-phase current.

3.1 Definition and origin of three-phase systems.
3.2 Star-delta connection.
3.3 Balanced three-phase systems.
3.4 Power in three-phase systems. Measuring systems.
3.5 Power factor. Definition, use and correction.
Unit 4. Direct current machines The objective of this topic is to understand the operation, parameters basic and utilities of a DC machine.

4.1 Basic constituent elements and operating principle.
4.2 Switching. Reaction of the armature.
4.3 Power balance and losses.
4.4 Excitation and equivalent circuits. Torque-speed curves.
4.5 Inversion of the direction of rotation and speed regulation.
Unit 5. Transformers This topic aims to understand the operation, basic parameters and uses of a transformer.

5.1 Principle of operation of transformers and main parts
5.2 Real transformer. Equivalent circuit.
5.3 Running regime.
5.4 Open and short circuit tests.
5.5 Losses and performance.
5.6 Excitation and connection current.
5.7 Constructive characteristics.
Unit 6. Asynchronous machines This topic aims to understand the operation, parameters and utilities of an asynchronous machine.

6.1 Principle of operation. Fundamental parts.
6.2 Equivalent circuit.
6.3 Open and short circuit tests.
6.4 Power balance. Rotational torque and maximum torque.
6.5 Start-up. Speed regulation
Unit 7. Synchronous machines This topic aims to understand the operation, parameters and utilities of a synchronous machine.

7.1 Principle of operation. Fundamental parts.
7.2 Types of excitation.
7.3 Linear and non-linear analysis. Equivalent circuit.
7.4 Alternator. Characteristics and applications.
7.5 Active and reactive power.
7.6 Balance of power, performance and torque.
7.7 Starting a synchronous motor
Practices Block I Practices related to electrical circuits
The aim of this group of practices is that the student understands the basic concepts of continuous, alternating and three-phase circuits, as well as a methodology for solving them. To do this, electronic instrumentation equipment will be used, as well as basic circuits assembled on prototyping boards.
In the practices of this block it will be proposed the assembly and analysis of electrical diagrams whose operation is not known a priori.

Practice 1: Introduction to the handling of instrumentation and assembly of basic direct current circuits.
The aim of this practice is to familiarize the student with the instrumentation equipment of the Electrotechnical Laboratory by means of the assembly of basic direct current circuits on a
prototyping (or protoboard). These circuits will include assemblies for series and parallel voltage measurement, as well as voltage and current dividers.
In this first practice of the subject, we will emphasize the precautions to be taken when handling electrical circuits, letting the student be aware of the dangers related to electric current, showing the basic electrical safety measures, the operation of the protective and safety equipment, and teaching hime/her how to manage dangers.

Practice 2: Assembly of direct current circuits
This practice aims to make more advanced circuits and aims to have the student experiment with resistive elements and sources on a prototype board. The student will check concepts seen in theory like Ohm's law, Thevenin's theorem, Boucherot's theorem, etc.

Practice 3: Assembly and measurement of alternating current circuits In this practice, the assembly of alternating current circuits is carried out in prototyping board, as well as learning how to use the functions and make measurements with the oscilloscope.

Practice 4: Simulation of PSIM circuits in alternating current The student will learn how to analyze a circuit in AC by means of the PSIM circuit simulation software.

Practice 5: Three-phase energy systems
The objective of this practice is to introduce students to the use of real three-phase systems. The sources in the lab will be used to feed passive loads and measure their consumption parameters with three-phase measuring equipment.
Practices Block II The purpose of this group of practices is for the student to understand the basic concepts of motors and electric machines. Panels with different electrical machines will be used, as well as simulation software.

In the practices of this block, tests or assemblies of machines without previous assembly guide will be proposed.

Practice 6: Single-phase transformer tests
The aim of this practice is to make the student aware of the main characteristics of a single-phase transformer. To this end, he will experimentally determine the parameters that govern its operation, using the so-called vacuum and short-circuit tests. The student must be able to carry out the appropriate assembly to perform these tests, measuring voltages, currents and powers.
From the result of the measurements the student has to be able to interpret the obtained data and extract from them the necessary information to know and quantify the different power losses in a real transformer. With these data he must build the equivalent model of a real transformer.
In this practice, the precautions to be taken when manipulating circuits and using electrical machines will be emphasized. In this sense, part of the practice will be dedicated to make the student aware of the dangers related to the electrical current, showing him the basic measures of electrical safety, the operation of the protection and safety devices, and teaching him how to manage the danger.

Practice 7: Three-phase asynchronous motor
The objective of this practice is that the student makes contact with an industrial asynchronous three-phase motor, identifying its windings, proposing its star and triangle connection, verifying its operation in no-load and making a change in the direction of rotation. Likewise, the problems originated by the loss of a phase in permanent regime and at the start will be analyzed.
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