JNTUK R20 2-1 DC Machines and Transformers Material PDF Download


JNTUK R20 2-1 DC Machines and Transformers Material PDF Download

Students those who are studying JNTUK R20 EEE Branch, Can Download Unit wise R20 2-1 DC Machines and Transformers Material/Notes PDFs below.


JNTUK R20 2-1 DC Machines and Transformers Material PDF Download

Preamble: This is a basic course on rotating electrical machines. This course covers the topics related to principles, performance, applications and design considerations of dc machines and transformers.

Course Objectives: This course is designed to:

  • To Understand the construction, principle of operation and performance of DC machines.  To Learn the characteristics, performance, methods of speed control and testing methods of DC motors.
  • To predetermine the performance of single phase transformers with equivalent circuit models.
  • To Understand the methods of testing of single-phase transformer.
  • To Analyze the three phase transformers and achieve three phase to two phase conversion


Electromechanical Energy Conversion and introduction to DC machines Principles of electromechanical energy conversion – singly excited and multi excited systemscalculation of force and torque using the concept of co-energy. Construction and principle of operation of DC machines – EMF equation for generator – Excitation techniques– characteristics of DC shunt generator –applications of DC Generators

Download UNIT-1 Material PDF | Reference-2 | Ref-3


Operation of DC motors Back-emf and torque equations of dc motors – Armature reaction and commutation – characteristics of separately-excited, shunt, series and compound motors – losses and efficiency – applications of dc motors. Necessity of a starter – starting by 3 point and 4-point starters.

Download UNIT-2 Material PDF | Reference-2 | Ref-3


Speed Control of motors and Testing of DC Machines Speed control by armature voltage and field control – testing of DC machines – brake test, Swinburne’s method – principle of regenerative or Hopkinson’s method – retardation test – field’s test- separation of losses.

Single-phase Transformers Types and constructional details – principle of operation –emf equation – operation on no load and on load – lagging, leading and unity power factors loads –phasor diagrams of transformers – equivalent circuit.

Download UNIT-3 Material PDF | Reference-2


Performance and testing of transformers and auto transformers: Regulation – losses and efficiency – effect of variation of frequency and supply voltage on losses – all day efficiency. Tests on single phase transformers – open circuit and short circuit tests – Sumpner’s test – separation of losses – parallel operation with equal voltage ratios – auto transformer – equivalent circuit – comparison with two winding transformers.

Download UNIT-4 Material PDF | Reference-2


3-Phase Transformer: Polyphase connections- Y/Y, Y/ Δ, Δ/Y, Δ/ Δ and open Δ- third harmonics in phase voltages – three winding transformers- transients in switching –off load and on load tap changersScott connection.

Download UNIT-5 Material PDF | Reference-2

Text Books:

  1. Electrical Machines by P.S. Bhimbra, Khanna Publishers,7th edition, 2011.
  2. Electric Machinery by A.E.Fitzgerald, Charleskingsley, Stephen D.Umans, TMH, 6 th edition, 2003.

Reference Books:

1. Electrical Machines by D. P.Kothari, I. J. Nagarth, McGraw Hill Publications, 4th edition, 2010.

2. Electrical Machines by R.K.Rajput, Lakshmi publications, 5th edition.

3. Electrical Machinery by Abijith Chakrabarthi and Sudhipta Debnath, McGraw Hill, 1st edition.

4. Electrical Machinery Fundamentals by Stephen J Chapman McGraw Hill education, 4th edition, 2010.

5. Electric Machines by MulukutlaS.Sarma & Mukeshk Pathak, CENGAGE Learning, 1st edition, 2008.

6. Theory & Performance of Electrical Machines by J.B.Guptha. S.K.Kataria& Sons, 1st edition, 2009.

Course Outcomes:

  • Assimilate the concepts of electromechanical energy conversion.
  • Mitigate the ill-effects of armature reaction and improve commutation in dc machines.
  • Understand the torque production mechanism and control the speed of dc motors.
  • Analyze the performance of single phase transformers.
  • Predetermine regulation, losses and efficiency of single phase transformers.
  • Parallel transformers, control voltages with tap changing methods and achieve three-phase to two-phase transformation.

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