Armature Winding (few definitions) Armature Winding (few definitions) Armature Winding (few definitions) Armature Winding (few definitions) Pole pitch : Distance between two adjacent poles.

Armature Winding (few definitions)….cont…. Armature Winding (few definitions)….cont…. g ( )g ( )

Conductor: The length of wire laying in themagnetic field and in which an emf is induced iscalled a conductor

EAB and CD are conductor

B D

Coil:The two conductor alongwith their end connectionconstitute one coil or armaturewinding ABEDC is a coil

A C

winding. ABEDC is a coil.

Types of DC generatorTypes of DC generatorTypes of DC generatorTypes of DC generator

- Separately excited DC generatorp y g- Self excited DC generator

- Shunt wound - Shunt wound - Series wound

C d d- Compound wound

Separately excited DC generatorSeparately excited DC generatorSeparately excited DC generatorSeparately excited DC generator

Rf

Vf

Ia= IL

Separately excited DC generator Separately excited DC generator (cont….)(cont….)

Field magnet winding is supplied from ang g ppindependent external d.c. sourceThe voltage output depends upon thee vo tage output epe s upo t espeed of rotation of armature and thefield currentThe greater the speed and field current,greater is the generated emfgreater is the generated emfSeparately excited d.c. generators arerarely used in practicerarely used in practice

Self excited DC generatorSelf excited DC generatorSelf excited DC generatorSelf excited DC generator

Field magnet winding is supplied current g g ppfrom the output of the generator itself

Series woundSeries woundSeries woundSeries wound

Series wound Series wound (cont….)(cont….)

The field winding is connected in seriesgwith armature winding so that wholearmature current flows through the fieldgwinding as well as the loadSince the field winding carries the wholegof load current, it has a few turns of thickwire having low resistanceg

Shunt woundShunt woundShunt woundShunt wound

Shunt woundShunt wound(cont….)(cont….)

The field winding is connected in parallelg pwith the armature winding so that terminalvoltage of the generator is applied across itg g ppThe shunt field winding has many turns offine wire having high resistanceg gTherefore, only a small part of armaturecurrent flows through shunt field windingcurrent flows through shunt field windingand the rest flows through the load.

Compound wound Compound wound Compound wound Compound wound In a compound-wound generator, there are twosets of field windings on each pole—one is inseries and the other in parallel with the armature.A compound wound generator may be:(a) Short Shunt in which only shunt field winding isin parallel with the armature windingin parallel with the armature winding

(b) Long Shunt in which shunt field winding is in(b) Long Shunt in which shunt field winding is inparallel with both series field and armaturewindingg

Compound wound (cont…)Compound wound (cont…)p ( )p ( )Short shunt

Compound wound (cont…)Compound wound (cont…)

Long shunt