Introduction to Machines
Subject Code: EPM1026
Aim of Subject: To introduce the basic concepts, general operating principles and construction of electrical machines.
Learning Outcome of Subject: At the completion of the subject, students should be able to:
  • Recognize the fundamental principles of electrical machines and three-phase systems.
  • Explain the construction, operation and applications of various generators, motors and transformers.
  • Distinguish the constructional details of induction machines and synchronous machines.
  • Construct the equivalent circuits and phasor diagrams for transformers and induction motors.
  • Analyse the torque-speed characteristics of three-phase induction motors.
Programme Outcomes:
  • Ability to acquire and apply fundamental principles of science and engineering. (60%)
  • Capability to communicate effectively. (10%)
  • Acquisition of technical competence in specialised areas of engineering discipline. (10%)
  • Ability to identify, formulate and model problems and find engineering solutions based on a systems approach. (10%)
  • Understanding and commitment to professional and ethical responsibilities. (5%)
  • Ability to work effectively as an individual, and as a member/leader in a team. (5%)
Assessment Scheme:
  • Lab Experiments - work in group of 2, lab report writing, oral assessment at the end of lab(10%)
  • Tutorial / Assignment - group assignment, focus group discussion at tutorial, to enhance understanding of basic concepts in lecture(10%)
  • Test Quiz - written exam(20%)
  • Final Exam - written exam(60%)
Teaching and Learning Activities: 53 hours (lectures, tutorials and laboratory experiments)
Credit Hours: 3
Pre-Requisite: ECT1016: Circuit Theory and
ECT1026: Field Theory
  • S. J. Chapman, "Electric Machinery Fundamentals" – 4th edition, McGraw Hill Higher Education, 2004. (Textbook)
  • B.S. Guru and H.R. Hiziroglu, "Electric Machinery and Transformers"-3rd edition, Oxford University Press, 2001.
  • T. Wildi, "Electrical Machines, Drives, and Power Systems"-5th edition, Prentice Hall, 2002.
  • P.C. Sen, "Principle of Electric Machines and Power Electronics"-2nd edition, John Wiley & Sons, 1997.

Subject Contents

  • Introduction to Machinery Principles

  • Introduction to electrical machines and transformers. Rotational motion, Newton's law, and power relationships. Magnetic field, Fraday’s law, induced voltage on a conductor moving in a magnetic field, production of force on a wire in a magnetic field.
  • Three-phase Circuits

  • Three-phase systems. Relation between line and phase quantities. Analysis of Balanced three-phase circuits. Y-? transformation. Power and reactive power calculations.
  • D.C. Machines

  • Principles of operation and construction of DC machines, simple armature windings: lap and wave. Emf equation and principle of commutation. DC generators: Separately excited, shunt wound, series wound and compound wound generators. Conditions for self-excitation of shunt-generator. Load characteristics and voltage regulation. DC motors: Torque equation, characteristics of shunt, series and compound motors. Starting and speed control. Tests, measurement and efficiencies of DC machines.
  • Transformers

  • Single-phase transformers: Construction, principle of operation and equivalent circuit, phasor diagram, efficiency and regulation. Short and open circuit tests. Parallel operation. Three phase transformers: Construction, Connections, and Parallel operation Autotransformers, Instrument transformers.
  • Induction Machines

  • Principles of operation and construction of three-phase induction motor. Slip equation, equivalent circuit, determination of equivalent circuit parameters by no-load and blocked-rotor tests. Losses, efficiency and torque. Torque-speed characteristics, starting torque and maximum torque. Starting methods. Introduction to single-phase induction motors.
  • Synchronous Machines

  • Principle of operation of Synchronous generators, Synchronous impedance and equivalent circuit. Short-circuit and open-circuit tests. Voltage regulation. Synchronizing procedures and parallel operation of synchronous machines. Principle of operation of synchronous motors, starting methods.


1. Load Test on DC Motors
2. Single Phase Transformer