FACULTY

APPLIED TECHNOLOGIES

DEPARTMENT

AIRCRAFT TECHNOLOGY ENGINEERING

LEVEL OF STUDIES

UNDERGRADUATE

MODULE CODE

AE2230T

SEMESTER OF STUDIES

4^TH

COURSE TITLE

ELECTRIC MACHINES

INDEPENDENT TEACHING ACTIVITIES

TEACHING HOURS PER WEEK

CREDIT UNITS

Lectures

3

3

Practice

1

2

COURSE TYPE

Specialty course

PRE-REQUIRED COURSES:

TEACHING AND EXAMINATION LANGUAGE

GREEK

THE COURSE IS OFFERED TO ERASMUS STUDETNS 

COURSE WEBSITE (URL)

Learning Objectives

The course aims at introducing students to the basic concepts of electric machines

After successfully completing the course, students should be able to:

–                     cope with the requirements of the international diploma examinations Part 66

–                     understand the principles of magnetism, induction and alternating current which the operation of electric machines is based on.

–                       describe the operation of ac generators and dc motors in the aircraft

–                     describe the operation of transformers, voltage regulators, rectifiers in the aircraft

–                     describe the operation of power distribution tables, circuit protection, batteries and emergency generatoin the aircraft

General Skills

•     Search, analysis and combination of data and information with the use of the necessary technologies

•     Adjustment to new conditions and technologies

•    Autonomous work

•    Group work

Unit 1: DC power generators and motors (total 8 hours)

              1.1.a) Magnetism  (Part 66 - Module 3.10)

             1.1.b  The theory of Generators and Direct Current motors    (Part 66 - Module 3.12)

              (Unit 1.1  4 hours) part 3.10 Μagnetism

               a)  The Theory of Magnetism. Magnet properties. Magnetic activity in the earth's magnetic field.          

               Magnetization and demagnetization. Magnetic shielding. Various types of magnetic materials. Construction 

               and operational principles of electromagnets. The rule of thumb for the magnetic field determination around

               a current carrying conductor. 

               b)  Magnetomotive force, field strength, field flux density, permeability, hysteresis loop, retentivity, coercive 

               force reluctance, saturation point, eddy currents. Protective measures for maintaining and storing magnets.

               Basic motor and generator theory. Construction and function of the DC generator components. Operation 

               and factors affecting the output current and its direction in DC motors. Operation and factors affecting the

               power output, torque, speed and rotation direction in DC motors. Series wound, shunt wound and compound 

                wound motors.  Starter generator construction.   

               1.2.a  DC Generator Construction characteristics / Dinstinction / Standardization / Usage / Application on 

                aircraft

               1.2.  b DC conventional motors, Servo motors, Stepper motors:  Construction characteristics / Dinstinction /  

               Standardization / Usage / Application on aircraft (Unit 1.2 , 4 hours)

Unit 2: Alternating Current Generators and Motors (8 hours total)

             2.1.a  The theory of alternating currents – Induction  (Part 66 - Module 3.11 & 3.13)

             2.1.b  Theory of AC Generators and Motors   (Part 66 - Module 3.17 & 3.18)

             (Unit  2.1, 4 hours) part

              3.11 Magnetic Induction / Induction coil . Faraday Law. Voltage induced in a magnetic field conductor.  

              Magnetic Induction principles. How the following factors affect the magnitude of the induced voltage:  

              magnetic field intensity, flow change rate, conductor number of windings. Mutual induction. How the primary

               current change rate and mutual induction affect induced voltage. Factors affecting mutual induction: coil

               number of windings, coil size, coil permeability, coil position. Lenz law and polarity determination rules.

               Inverse electromotive force, self induction. Saturation point. Common applications of induction coils.

               Part 3.13 The theory of Alternating Current (AC) . Sinusoidal waveform: phase, period, frequency, cycle. 

               Instantaneous, average, root mean square, peak, peak to peak  current values and their calculation in relation 

               to voltage, current intensity and power. Triangular/square waveforms. Single phase/three phase operation

               principles. 

               Part 3.17 AC Generators . Loop rotation in magnetic field and waveform produced. AC generator operation 

               and construction with rotating cage and rotating field. Single phase, double phase and three phase 

               alternators. Advantages and uses of three phase star and triangle connection. Permanent magnet generators.

               Part 3.18 Alternating Current (AC) Motors . Construction, operation principles and characteristics of  

               synchronous AC motors and induction AC motors, single phase and multi phase. Speed and rotating direction

                control methods. Methods of creating  a rotating field: capacitor,   induction coil, covered or split pole.  

                2.2.a  Construction elements / Distinction / Standardization / Usage of AC Generator,  applications on aircraft

                2.2.b  Construction elements / Distinction / Standardization / Usage of  AC conventional motors/Permanent 

                magnet motors/ Electric motors as actuators,  applications on aircraft (Unit 2.2, 4 hours)

Unit 3: Τransformers) (Part 66 - Module 3.15)

            (Unit 3, 2 hours) part 3.15 Transformers

            Transformer construction and operation principles. Transformer losses and methods of loss reduction. 

              Transformer operation under load and in vacuum. Power transmission, efficiency, polarity marking.

              Calculations of voltages and power line currents and phase. Power calculation in three phase system.  Current, 

              voltage, winding ratio, power, primary and secondary performance

Unit 4: Voltage regulation / Rectifiers / Inverters

(Unit 4, 2 hours)

Unit 5: Power distribution tables/ circuit protection / Batteries

(Unit 5, 2 hours)

Unit 6: Emergency power generator

Electric Power (External/Ground power), (Unit 6, 2 hours)

ΤEACHING METHOD

Lectures in the classroom

USE OF INFORMATION AND COMMUNICATION TECHNOLOGIES  

TEACHING ORGANIZATION

STUDENT EVALUATION

Final writen examination including:

•               Multiple choice questions 

•               Problem solving questions on magnetism, induction, alternating current, motor/generator/transformer construction principles

•               Short answer questions

•               Topic development

-Suggested Bibliography :ΗΛΕΚΤΡΙΚΕΣ ΜΗΧΑΝΕΣ AC / DC Stephen Chapman (Εκδόσεις Τζιόλα)