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## Electrical Machines-I

### Preamble:

This can be a basic course on rotating electrical machines. This course covers the topics associated with principles, performance, applications and style issues of dc machines and transformers.

#### Learning objectives:

• perceive the unifying principles of magnetic attraction energy conversion.

• perceive the development, principle of operation and performance of DC machines.

• Learn the characteristics, performance,methods of speed management and testing ways of DC motors.

• To predetermine the performance of single part transformers with equivalent circuit models.

• perceive the ways of testing of single-phase electrical device.

• Analyze the 3 part transformers and win 3 part to 2 part conversion.
UNIT–I: mechanical device Energy Conversion and introduction to DC machines Principles of mechanical device energy conversion – separately excited and multi excited system – Calculation of force and torsion victimisation the thought of co-energy. Construction and principle of operation of DC machine – electromotive force equation for generator – Classification of DC machines supported excitation – OCC of DC shunt generator.

#### UNIT–II:

Performance of D.C. Machines torsion and back-emf equations of dc motors– coil reaction and commutation – characteristics of separately-excited, shunt, series and compound motors – losses and efficiency- applications of dc motors.

#### UNIT-III:

beginning, Speed management and Testing of D.C. Machines Necessity of starter – beginning by three purpose and four purpose starters – Speed management by coil voltage and field management – take a look ating of DC machines – brake test, Swinburne’s technique – principle of regenerative or Hopkinson’s technique – retardation take a look at — separation of losses.

#### UNIT–IV:

Single-phase Transformers sorts and constructional details – principle of operation – electromotive force equation – operation on no load and on load – insulation, leading and unity power factors hundreds – phasor diagrams of transformers – equivalent circuit – regulation – losses and potency – result of variation of frequency and provide voltage on losses – All day potency.

#### UNIT-V

Single-phase Transformers Testing Tests on single part electrical devices – electrical circuit and tangency take a look ats – Sumpner’s test – separation of losses – simultaneous operation with equal voltage ratios – automotive vehicle transformer – equivalent circuit – comparison with 2 winding transformers.

#### UNIT-VI

3-Phase Transformers multiphase connections – Y/Y, Y/∆, ∆/Y, ∆/∆ and open ∆ — Third harmonics in part voltages – 3 winding transformers: determination of Zp, Zs and Zt — transients in switch – off load and on load faucet changers — Scott affiliation.

#### Learning outcomes:

• able to assimilate the ideas of mechanical device energy conversion.

• able to mitigate the ill-effects of coil reaction and improve commutation in dc machines.

• able to perceive the torsion production mechanism and management the speed of dc motors.

• able to analyze the performance of single part transformers.

• able to predetermine regulation, losses and potency of single part transformers.

• able to parallel transformers, management voltages with faucet dynamic ways and win three-phase to two-phase transformation.

#### Text Books:

one. Electrical Machines – P.S. Bhimbra, Khanna Publishers two. electrical Machinery by A.E.Fitzgerald,Charleskingsley,StephenD.Umans, TMH

#### Reference Books:

one. Electrical Machines by D. P.Kothari, I .J .Nagarth,McGrawHill Publications, fourth edition

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

3. Electrical Machinery by AbijithChakrabarthi and SudhiptaDebnath,McGraw Hill education 2015

four. Electrical Machinery Fundamentals by Stephen J Chapman John McGraw Hill education 2010

five. electrical Machines by MulukutlaS.Sarma&Mukeshk.Pathak, CENGAGE Learning.

6. Theory & Performance of Electrical Machines by J.B.Guptha. S.K.Kataria& Sons