Complementos de Máquinas Elétricas

Electrical Circuit Theory I and II

Electrical Machines

Theoretical classes with exposition 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 link 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 solving classes, which implement the models presented in the theoretical classes, allowing the calculation of the parameters of the machines studied from test results and their operating regimes; and laboratory experimentation classes where the classic tests of the studied machines are carried out.

Goals
The main aims of this course unit are:
Understand the steady state operation of direct current machines, synchronous machines and special electrical machines of more common use (universal motor, permanent magnet motor and reluctance motor). Knowledge of mechanical construction, principle of operation and equivalent circuits of dc machines and synchronous machines. Familiarize students with these electrical machines in electrical machines laboratory environment.

Skills
At the end of this course unit the learner is expected to be able:
To test, connect and work with dc machines and synchronous machines.
To design and conduct experiments, as well as to analyze and interpret data.
To choose technical solutions and participate in projects to implement and maintain these machines.

1. DC machines

Mechanical construction. Principle of operation. Armature windings. Emf equation. Armature reaction. Theory of commutation. Power balance, developed torque, and efficiency. Excitation systems. Characteristics of the separately excited, shunt, series and compound generators. Characteristics of the separately excited, shunt, series and compound motors. Starting, braking and reversing operation of dc motors. Speed regulation.

2. Synchronous machines

Principle of operation. Physical constitution. Ac windings. Induced emf equation. Time and space harmonics. Armature reaction. Synchronous generators: Load operation. Economic tests and generators characteristics. Equivalent circuits. Parallel operation. Synchronous Motors: Power and torque for single-phase and three-phase motors. Effects of excitation and load. Power factor correction. Start of synchronous motors.

3. Special-purpose electric machines

Universal motors, Permanent-magnet motors. Reluctance motors.

NAO

See above