ELECTRICAL MACHINES (CCE)

SHE Level 2
SCQF Credit Points 20.00
ECTS Credit Points 10.00
Module Code M2H624675
Module Leader Alan Nesbitt
School School of Computing, Engineering and Built Environment
Subject SCEBE - School Office
Trimesters
  • A (September start)
  • B (January start)

Pre-Requisite Knowledge

Electro-Mechanical Workshop/Electrical Machines Lab

Summary of Content

This module is focused on basics of electrical equipment and machines. It provides the foundation for electrical engineers by developing understanding of working principles of transformers, ac machines and dc machines. Application of engineering basics to evaluate and analyze the performance characteristics of machines is also covered in module.

Syllabus

1-Phase Transformer: Single phase transformer - Constructional details, principle of operation, EMF equation, no-load and load operation, equivalent circuit, voltage regulation and efficiency. 3-phase Transformer: Constructional features of three phase transformers - three phase connection of single phase transformers - oscillating neutral - tertiary winding - Scott connection - open delta connection, load sharing - distribution transformers - all day efficiency. Autotransformers - saving of copper - applications - tap-changing transformers - cooling of transformers Induction Motors: Construction - squirrel cage and slip-ring motor - principle of operation - slip and frequency of rotor current - mechanical power and developed torque - phasor diagram - torque slip curve - pull out torque - losses and efficiency No load and locked rotor tests - equivalent circuit - performance calculation from equivalent circuit - circle diagram - operating characteristics from circle diagram - cogging and crawling and methods of elimination. Synchronous Machines: Types - selection of alternators - constructional features of cylindrical and salient pole machines DC Motors: Performance characteristics of shunt, series and compound wound motors - starting - 3-point and 4-point starters - Calculation of resistance elements for shunt motor starters - methods of speed control of shunt, series and compound wound motors - effect of an open field circuit - power flow diagram - efficiency - testing D.C machine - Swineburne's test - Hopkinson's test - Field's test - Retardation test DC Generator : Types of excitation - separately excited - self excited shunt, series and compound machines. Load characteristics of generators ,parallel operation of shunt, series and compound generators - equalizer connection - Losses - power flow diagram - efficiency, and applications

Learning Outcomes

On completion of this module the student should be able to know:1. Explain operation of the single phase transformer at no load and on load condition with the help of phasor diagrams and equivalent circuit. (AM1, AM5)2. Calculate efficiency of a transformer at any load condition using open circuit and short circuit test data. (AM1, AM5)3. Sketch four types of three phase transformer winding connections and list their applications. (AM1, AM5)4. Draw and explain operating characteristics of dc machines (Motors & Generators). (AM1, AM9)5. Evaluate and determine power flow, losses and efficiency for dc machine control schemes. (AM1, AM9)6. Explain operation and torque-slip characteristic of different types of three phase induction motors. (AM1, AM5)7. Perform calculations for no load and blocked rotor tests on three phase induction motor to determine its losses and efficiency. (AM1, AM5)8. Justify the application of a particular type of synchronous generator for different applications. (AM1)

Teaching / Learning Strategy

The main teaching method will be based on lectures with laboratory exercises offered in dedicated lab module used to relate theoretical concepts to practical experience. The students will be expected to perform directed reading exercises and self-learning exercises on topic related to Electrical Machines. Tutorials will be used to reinforce the module material and to discuss the issues raised by the directed reading.

Indicative Reading

-360 1. Stephen J Chapman, " Electric Machinery and Power System Fundamentals", Mac-Graw Hill, 2001 -360 2. Theodore Wildi, "Electrical Machines, Drives, and Power Systems", Pearson Education Asia, New Delhi.4 th Edition, 2006. -360 3. P.CSen, "Principles of Electric Machines and Power Electronics", John Wiley and Sons, 2003 4. Alexander Langsdorf, "Theory of Alternating Current Machinery" TataMac-GrawHill, 2 nd Edition, 2001. B.L.Theraja and A.K. Theraja, Text book of Electrical Technology", Vol. 1 and 2, S.Chand Publication, 2005.

Transferrable Skills

Tutorials provide, Problem Solving and Numeracy, use of IT and Interpersonal/team skills, Communication/Literacy/Linguistic/Critical Evaluation

Module Structure

Activity Total Hours
Independent Learning (FT) 100.00
Assessment (FT) 16.00
Tutorials (FT) 28.00
Lectures (FT) 56.00

Assessment Methods

Component Duration Weighting Threshold Description
Exam (School) 1.50 20.00 35% Mid-term test - Unseen Test: 1 hour 30 minutes
Coursework 1 n/a 30.00 35% Design task report 1500 words
Exam (Exams Office) 2.00 50.00 45% Final Examination - unseen exam: 3 hours