DC motor construction & principle of operation.ppt

Introduction of electromagnetic Induction, Faraday's Laws of Electromagnetic Induction,Faraday's Experiment setup, Fleming’s Right hand Rule, Lenz’s Law.
Applications of DC Motor,DC motor construction & principle

1. Content
1Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
DC motor construction & principle of operation.

2. Introduction
2Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
AdirectcurrentorDCmotor,convertselectricalenergyintomechanicalenergy.
Insomeapplications,itisalwaysbeneficialtouseDCmotorforexample,mines
,mills,electrictrainsetc.
ThecharacteristicsofDCmotorsaresuperiorthanACmotors.
AmongDCmotors,thereareshunt-wound,series-wound,
compound-woundandpermanentmagnetmotors.

3. 2.4Faraday'sLawsofElectromagneticInduction,
Fleming’sRighthandRule,Lenz’sLaw.
3Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale

4. Introduction
4Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Thephenomenonbywhiche.m.f.isobtainedfromfluxiscalled
electromagneticinduction.
Faraday'slawofinductionisoneoftheimportantconceptsof
electricity.
Itlooksatthewaychangingmagneticfieldscancausecurrentto
flowinwires.
Basically,itisaformula/conceptthatdescribeshowpotential
difference(voltagedifference)iscreatedandhowmuchiscreated.

5. Faraday's Experiment
5Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Consideracoilhaving'N'turnsconnectedtoagalvanometerasshownin
theFig.
Galvanometerindicatesflowofcurrentinthecircuit,ifany.

6. Faraday's Experiment
6Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Apermanentmagnetismovedrelative
tocoil,suchthatmagneticlinesofforce
associatedwithcoilgetchanged.
Whenever,thereismotionofpermanent
magnet,galvanometer deflects
indicatingflowofcurrentthroughthe
circuit.

7. Continue
7Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
Thedeflectioncontinuesaslongasmotionofmagnetexists.
Morequicklythemagnetismoved,thegreateristhedeflection.
Nowdeflectionofgalvanometerindicatesflowofcurrent.
Buttoexistflowofcurrenttheremustbepresenceofe.m.f.
Hencesuchmovementoffluxlineswithrespecttocoil
generatesane.m.f.whichdrivescurrentthroughthecoil.

8. 8Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
Faraday’slawofelectromagneticinduction(referredtoasFaraday’s
law)isabasiclawofelectromagnetism,predictinghowamagneticfield
willinteractwithanelectriccircuittoproduceanelectromotiveforce
(EMF).Thisphenomenonisknownaselectromagneticinduction.
Faraday's Law

9. 9Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
Faraday's First Law -
Statement -
Whenever the number of magnetic lines of force (flux) linking
with a coil / or circuit changes, an e.mf. gets induced in that coil
or circuit.

10. 10Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
Faraday's Second Law -
Statement–
Themagnitudeoftheinducede.m.f.isdirectlyproportionaltotherateof
changeoffluxlinkages(fluxxturnsofcoil).
OR
Itstatesthatthemagnitudeofinducedemfinthecoilisequaltotherateof
changeoffluxthatlinkageswiththecoil.Thefluxlinkageofthecoilisthe
productofthenumberofturnsinthecoilandfluxassociatedwiththecoil.

11. Continue
11Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale

12. Lenz’s Law
12Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale

13. Fleming’s Right hand Rule
13Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
Statement-
Stretchouttheforefinger,middlefinger
&thumbofyourrighthand,sothatthey
areatrightanglestooneanother.
Iftheforefingerpointsinthedirectionof
magneticfield,Thumbinthedirectionof
motionoftheConductorandmiddle
fingerinthedirectionofInducedemf.

14. Continue
14Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale

15. Summery…
15Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
Faraday’slawstatesthatacurrentwillbeinducedinaconductorwhich
isexposedtoachangingmagneticfield.
Lenz’slawofelectromagneticinductionstatesthatthedirectionofthis
inducedcurrentwillbesuchthatthemagneticfieldcreatedbythe
inducedcurrentopposestheinitialchangingmagneticfieldwhich
producedit.
ThedirectionofthiscurrentflowcanbedeterminedusingFleming’s
right–handrule.

16. Working Principle of D.C. Motor
16Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
WorkingPrincipleofD.C.Motor:
Amachinethatconvertsd.c.powerintomechanicalpowerisknownasad.c.
ItsoperationisbasedontheprinciplethatWhenaCurrentcarryingconductor
placedinamagneticfield,Itexperiencesaforce.Thedirectionofthisforceis
givenbyFleming’sLeftHandruleandmagnitudeisgivenby,
F = B I L Newton.

17. 17Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
Dc motor consists of :
Stator :it’s the stationary part containing the field winding and receives the
supply.
Rotor :which is the rotating part.
TheconstructionofDCmachinecanbedoneusingsomeoftheessentialpartslike
Yoke,Polecore&poleshoes,Polecoil&fieldcoil,Armaturecore,Armature
windingotherwiseconductor,commutator,brushes&bearings.Someof
theimportantpartsoftheDCmachineisdiscussedbelow.

18. 18Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
Dc motor consists of :
Stator :it’s the stationary part containing the field winding and receives the
supply.
Rotor :which is the rotating part.
TheconstructionofDCmachinecanbedoneusingsomeoftheessentialpartslike
Yoke,Polecore&poleshoes,Polecoil&fieldcoil,Armaturecore,Armature
windingotherwiseconductor,commutator,brushes&bearings.Someof
theimportantpartsoftheDCmachineisdiscussedbelow.

19. 19Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Construction of D.C. Motor

20. 20Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,

21. 21Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
1)Yoke–
Theouter&themainframeofthemachineiscalledasyoke.
Itismadeupofcaststeelandcastiron.
Theyokeservesthefollowingtwopurposes.
i)Itsupportstheothercomponentssuchaspolesandprovidesmechanical
protectionforwholemachine.
ii)ii)Itformsapartofthemagneticcircuit&providesthepathoflow
reluctanceforthemagneticflux.

22. 22Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
2)Pole-Therearetwotypesofpole.
Polecore-Thepoleshoeservestwopurposes
i)Theyspreadoutfluxintheairgap&theirlargecross-
sectionreducesthereluctanceofthemagneticpath.
i)Theysupporttheexcitingcoilsorfieldcoils.
Poleshoes–
PoleshoeinDCmachineisanextensivepartaswellasenlargetheregionofthe
pole.Becauseofthisregion,fluxcanbespreadoutwithintheair-gapaswellas
extrafluxcanbepassedthroughtheairspacetowardarmature.

23. 23Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
3)Armaturecore:–
Armaturecoreincludesthehugenumberofslots
withinitsedge.Armatureconductorislocatedin
theseslots.
Itprovidesthelow-reluctancepathtowardtheflux
generatedwithfieldwinding.

24. 24Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
4)Armaturewinding:–
Thearmaturewindingconsistsoflargenumberof
coilsorconductorssuitablyconnectedtogether.
Whenweuseaprimemovertorotatethe
armature,amagneticfluxandvoltageinduced
init.
It’simportantbecauseitcarriesthecurrent
suppliedtothemachine.

25. 25Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
5)Commutator:–
Themainfunctionofthecommutatorinthe
DCmachineis-
Tocollectthecurrentfromthearmature
conductoraswellassuppliesthecurrentto
theloadusingbrushes.
Andalsoprovidesuni-directionaltorquefor
DC-motor.

26. 26Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
6)Brushes:–
BrushesintheDCmachinegatherthecurrent
fromcommutatorandsuppliesittoexterior
load.
Itisusedtoinjectorcollectcurrentfrom
rotatingarmaturewinding.
Tofacilitateelectricalconnectionofrotating
armaturewindingtoexternalstationarycircuit.

27. 27Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
7)Bearings:–
Bearingsareusedto
Tosupporttherotorandreducefrictionfor
smoothrotationofrotor.
Maintainsrotorinafixedphysicalposition
relativetothestator

28. 28Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Continue
8)Shaft:–
Usedtotransfermechanicalpower.
ShaftofDCMotoriscoupledtotheload
totransfermechanicalpower.

29. 29Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
9)AirGap–
•Theairgapofamotoristhegap
betweenthestatorteethorcoreand
therotormagnets.
•Thisgapisakeycomponentinthe
motordesign,andaffectstheoverall
strengthofthemagneticcircuitand
motorefficiency.

30. 30Department Of Mechatronics, Sanjivanicollege of Engineering, Kopargaon Prof. S.C.Bhangale
As current in coil changes,
Applications of DC Motor
Directcurrent(DC)machineshavenumerousapplications.
Theseapplicationsrangefromourdailylifetospacecraftapplications.
Inourdailylife,theyareusedin
printers,fuelpumps,andelectricvehicles.
Whileinspacecraftapplications,theyareusedinsolar
airplane,electricaircraft,andpropulsionsystems.