Module 1
D.C Machines: Generation of D.C – Action of Commutator – constructional details of D.C machine – magnetic circuit of D.C machines – D.C Armature windings – Induced emf – emf equation – torque developed in a D.C machine – generator and motor action – back emf – Armature mmf – magnitude and direction – Air-gap flux distribution curve on load – effect of saturation – Demagnetising and cross – magnetising armature mmf – variation with brush position – compensating winding – Commutation – time of commutation – emf in coil undergoing commutation – reactance emf – effect of brush shift – inter-poles.
Module 2
D.C Generator: Types of excitation – separately excited – self excited shunt, series and compound machines. OCC – Condition for self excitation – field critical resistance – critical speed – Load characteristics of generators – Load critical resistance – parallel operation of shunt, series and compound generators – equalizer connection – Losses – power flow diagram – efficiency - condition for maximum efficiency – applications – special machines – welding generator – Boosters.
Module 3
D.C 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.
Module 4
Transformers: Single phase transformer – Constructional details – Core – windings – Insulation – principle of operation – Inrush of switching currents – emf equation – magnetising current and core losses – no-load and load operation – Phasor diagram – equivalent circuit – losses and efficiency – condition for maximum efficiency – voltage regulation – approximate expression for voltage regulation – harmonics in single phase transformers - Magnetising current wave form – OC and SC tests – Sumpner’s test.
Module 5
Three phase Transformer: Constructional features of three phase transformers – three phase connection of single phase transformers – oscillating neutral – tertiary winding – Scott connection – open delta connection – three phase to six phase connection – equal and unequal turns ratio – load sharing – distribution transformers – all day efficiency. Autotransformers – saving of copper – applications - tap-changing transformers - cooling of transformers.
References
The performance and Design of Direct Current Machines: A. E. Clayton and N. N Hannock
AC Machines: M.G. Say
Theory of Alternating Current Machinery: Alexander Langsdorf, TMH
Electrical Machines: R.K Rajput
mg university B.tech Syllabus S3 Electrical and Electronics EEE
Custom Search