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DI03000081 · Semester 3 · 5G scheme

Electrical Machines - I

Notes and solutions following the Gujarat Technological University (GTU) syllabus for DI03000081. Independent material — not issued by the university.

Electrical EngineeringRenewable Energy

Materials

Syllabus

The official syllabus this material follows.

  • Syllabus

    10 pages

    FreeRead

Complete Book

The whole syllabus, unit by unit, written for the exam.

Slides

Lecture slides for revision.

Past Papers

Original question papers from previous exams.

  • Summer 2026 question paper

    3 pages

    FreeRead

  • Winter 2025 question paper

    3 pages

    FreeRead

PYQ Solutions

Past university papers, fully solved.

  • Solved past papers — detailed answers

    35 pages · English + ગુજરાતી

    Premium Preview · 5 pages

Syllabus units

Unit 1: DC Generators
  • D.C. Machine: construction, parts-function and material
  • D.C. Generator: Principle of operation, Faraday's law of electromagnetic induction, Fleming's right-hand rule.
  • E. M. F. equation of D.C. Generator (Derivation).
  • Types of D.C. Generator and it's applications.
  • Characteristics -Magnetic, internal and external.
  • Armature Reaction and Commutation (Briefly).
  • DC Machine: Power Stages, losses, voltage regulation and efficiency.
Unit 2: D.C. Motors
  • Principle of operation, Lorentz force, Fleming's Left-hand rule, Back emf and it's significance.
  • Torque: armature torque, shaft torque, Break Horse Power (BHP).
  • Types of D.C. Motors, D. C. Motor characteristics: speed-armature current, torque-armature current, speed-torque.
  • Speed control: D.C. shunt and series motor - flux and armature control, Numerical.
  • Starters, necessity of starters, two-point starters, three-point starters
  • Testing of D.C. Machines. (Brake test, Swinburne's test).
  • D.C. Motors applications, advantages and disadvantages.
Unit 3: Single phase transformers
  • Introduction, Types of transformers: Shell type and Core type, construction, parts-functions and materials used for different parts.
  • Principle of operation, EMF equation, voltage transformation ratio, turns ratio, Numerical.
  • Significance of transformer ratings.
  • No-load and On-load test on transformer and it's phasor diagram, Leakage reactance.
  • Equivalent circuit of transformer with equivalent resistances and reactances.
  • Voltage regulation and Efficiency: Direct load Test, O.C. / S.C. Test, Polarity Test. All day efficiency, Numerical, Applications.
  • Single phase auto transformer: Construction and working.
Unit 4: Three phase transformers
  • Introduction, Working principle of three phase transformer.
  • Construction, bank of three single phase transformers. Single unit of three phase transformer, Cooling Methods.
  • As per IS: 10028 (Part I)-1985 - Selection criteria of distribution transformer and power transformer.
  • As per IS: 2026 (part IV)-1977 - Winding Connections / Vector group of three phase transformers (Star-Star, Delta-Delta, Delta-Star, Star-Delta, Open Delta or V -V connection), Three phase to two phase conversion (Scott Connection), Numerical.
  • Need of parallel operation, conditions for parallel operation.

About this course

Despite technological advancements in electrical technology, DC machines continue to play a significant role in many industrial and commercial applications. Transformers play a critical role in modern power systems, ensuring efficient energy transmission and distribution. This course provides students with core principles and hands-on skills in electrical machines. It builds a strong theoretical and practical foundation for careers in electrical engineering and related fields. By the end of the course, Learners will gain expertise in key components like DC machines and Transformers, preparing them for industry demands.