ENG2029 : Introduction to AC Electrical Machines and Drives

• Offered for Year: 2021/22
• Module Leader(s): Dr Andrew Smith
• Owning School: Engineering
• Teaching Location: Newcastle City Campus
Semesters
 Semester 2 Credit Value: 10 ECTS Credits: 5

Aims

To introduce students to topics in electrical engineering including polyphase circuits, polyphase synchronous machines, polyphase induction machines, three-phase transformers, three phase distribution systems, and electric drives.

Outline Of Syllabus

Polyphase Circuits:       Balanced 3 phase circuits; 3 phase phasor representations; summation of currents to zero; neutral, star, and delta connections.

Polyphase Synchronous Machines:       Production of rotating field by balanced excitation of the polyphase windings; concept and theory of synchronous operation; theory of synchronous machine with uniform airgap. Equivalent circuits, voltage equations, alternative sink and source conventions, typical phasor diagrams, electrical power as a function of load angle; operation characteristics with constant power and varying excitation, relationships to phasor diagrams; torque angle.

Polyphase Induction Machines:             Transition from synchronous to asynchronous operation; derivation of exact equivalent circuit; modification of exact equivalent circuit by application of Thevenin’s theorem; relationships between 'rotor current', mechanical power, and torque; condition for torque to be maximum; effect of changing rotor resistance on current and torque characteristics.

Electrical Drives:       Review of simple AC drives, 3-phase PWM voltage source inverter; freewheel diode function, dead-time requirements; analogue implementation of 3-phase PWM, constant volts per hertz control of an induction machine; Basic PM synchronous motor drive.

Three-phase Transformers:       3 phase transformer construction; star and delta connections and effect on primary / secondary voltages and currents; phase shifts; reflected impedance.

Three phase Distribution Systems:       3-phase power system analysis; per-unit system; reasons for per- units; choice of base, single phase representation of balanced polyphase operation.

Teaching Methods

Teaching Activities
Category Activity Number Length Student Hours Comment
Guided Independent StudyAssessment preparation and completion16:006:00Writing of summatively assessed lab report
Guided Independent StudyAssessment preparation and completion12:002:00Summatively assessed Closed Book final Exam in Assessment Period.
Guided Independent StudyAssessment preparation and completion181:0018:00Revision for final exam
Scheduled Learning And Teaching ActivitiesLecture180:309:00Non-synchronous lecture replacement videos
Scheduled Learning And Teaching ActivitiesPractical13:003:00PiP Matlab session on Machines. Week 7 of term
Scheduled Learning And Teaching ActivitiesPractical13:003:00PiP Matlab session on Electric Drives. Week 9 of term
Scheduled Learning And Teaching ActivitiesSmall group teaching101:0010:00PiP tutorial per week from 2nd week,
Scheduled Learning And Teaching ActivitiesDrop-in/surgery31:003:00Three one-hour surgery sessions
Guided Independent StudyIndependent study181:0018:00Student reflection of Recorded Lecture Materials and Notes
Guided Independent StudyIndependent study281:0028:00Reviewing lecture notes; general reading
Total100:00
Teaching Rationale And Relationship

The online lecture replacement videos provide the core material for the course.

Problem solving is introduced and practiced through present in person tutorial sessions.

The computer-based machines and electric drives sessions provides an opportunity to gain practical experience with Matlab / Simulink and helps students understand and validate the theory introduced in the lectures.

Assessment Methods

The format of resits will be determined by the Board of Examiners

Exams
Description Length Semester When Set Percentage Comment
Written Examination1202A802 hour invigilated closed-book exam
Other Assessment
Description Semester When Set Percentage Comment
Practical/lab report2M20Laboratory report covering the Induction and Synchronous Machines experiments. Maximum of 2000 words.
Assessment Rationale And Relationship

The examination allows students to demonstrate their ability to solve engineering problems based around 3 phase systems including AC induction and synchronous machines, electric drives, and transformers, using the knowledge and methodology presented in the course material.
The computer-based machines experiments allow students the opportunity to understand and validate the theory taught on the course in a practical setting

I will investigate if the 2-hour invigilated closed book exam can be replaced by an online test, but due to the nature of the material in this course, it cannot be guaranteed that this is feasible.