Accionamentos Eletromecânicos

Electrical Installations I

Electrical Machines I and II

Power Electronics

(THIS SUBJECT IS TEACHED ONLY IN PORTUGUESE)

Theoretical classes: with exposure of the subjects, drawing attention to the most relevant aspects and making the connection between each subject and the others. Interpellation of students on the subject in order to arouse curiosity, remember and connect previous knowledge. Presentation of some videos and animations that illustrate the concepts and / or applications.

Practical / Laboratory Classes. These classes are of two types: Exercise resolution classes, with analysis and dimensioning of electromechanical drives, including their command and protection; and laboratory experimentation classes where different electromechanical drives are tested, controlled and connected.

 The UC organization, carefully balancing comprehensive theoretical knowledge with resolution of theoretical-practical exercises and laboratory practice, makes this one of the most successful UCs in LEE, with a very high approval rate for the students evaluated. For the motivation of the students, it also contributes the attribution of one or two certificates (depending on the results obtained in the UC and in the laboratories) awarded by SEW Eurodrive, under the protocol between ISEC and this reference company in the area of electromechanical drives.

To give students theoretical, practical and experimental skills on electromechanical drives and on the respective protection, command and control devices. At the end of this course unit, the student is expected to be able to use, design, analyze, optimize, protect and implement electromechanic drives, integrating three-phase induction motors, soft-starters, variable-speed drives, contactors, protection devices and mechanical transmission. From a general perspective, students should acquire the capacity to make judgments and make decisions related to theoretical and practical knowledge acquired and promote the exchange of ideas and the discussion of problems and solutions, develop a professional attitude towards work and acquire habits of self-learning.

1 – Introduction to electromechanical drives

Energy conversion and electromechanical drives. Constant and variable speed electromechanical drives. Fundamental equation of dynamics. Inertia, friction and elastic effects. Types of loads. Mechanical transmissions and applications.

Models and equivalent schemes of three-phase induction motor.

2 – Speed control, torque and position

Soft starters and variable frequency drives; Main functions; Scalar control (“V/f” and “E/F”) and vector control. Speed and position transducers.

3 – Design, analysis and optimization of motive power electrical systems 

Electromechanical drives efficiency and reliability. Equipment selection and sizing.

Contactors and relays. AC and DC feed coils. Contactor selection according to the application. Electromagnetic and thermal effects of short circuits. Coordination types. Solutions with 1, 2 or 3 devices for performing the basic functions of a motor output.

Standards and symbols for electrical diagrams. 

Induction motor starting methods and associated control and power circuits.

Thermal behavior of electric motors. Operating temperature and lifetime. Operating range of electric motors and electronic variable speed drives. Oversizing and power quality impact in the performance of induction motors.

Induction motors and electronic variable speed drives standards. Insulation classes and motor mounting arrangements (positions). Motor duty cycles.

Potential for energy savings. International Efficiency classes. Turnaround time of investment. Different technological combinations. 

4 – Special and Emerging Technologies

Permanent magnet motors. Reluctance motors. Linear induction motors and reluctance.

NOTE: In order to ensure the coordination of measures between the theoretical and laboratory practice, the teaching sequence of the materials may not be exactly the shown above. 

NAO