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Maxwell v11Transient

Getting Started with Maxwell:Transient Problem

June2005

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Theinformationcontainedinthisdocumentissubjecttochangewithoutnotice.

Ansoftmakesnowarrantyofanykindwithregardtothismaterial,including,but

notlimitedto,theimpliedwarrantiesofmerchantabilityandfitnessforaparticular

purpose.Ansoftshallnotbeliableforerrorscontainedhereinorforincidentalorconsequentialdamagesinconnectionwiththefurnishing,performance,oruseof

thismaterial.

2005AnsoftCorporation.Allrightsreserved.

AnsoftCorporation

225WestStationSquareSuite200

Pittsburgh,PA15219

USA

Phone:412-261-3200Fax:412-471-9427

MaxwellandOptimetricsareregisteredtrademarksortrademarksofAnsoftCor-poration.Allothertrademarksarethepropertyoftheirrespectiveowners.

Neweditionsofthismanualwillincorporateallmaterialupdatedsincetheprevi-

ousedition.Themanualprintingdate,whichindicatesthemanualscurrentedi-

tion,changeswhenaneweditionisprinted.Minorcorrectionsandupdatesthat

areincorporatedatreprintdonotcausethedatetochange.

Updatepackagesmaybeissuedbetweeneditionsandcontainadditionaland/or

replacementpagestobemergedintothemanualbytheuser.Pagesthatarerear-rangedduetochangesonapreviouspagearenotconsideredtoberevised.

Edition Date Software

Version

1 June 2005 Maxwell 11

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Getting Started with Maxwell: Transient Problem

iii

Conventions Used in this GuidePleasetakeamomenttoreviewhowinstructionsandotherusefulinforma-

tionarepresentedinthisguide. TheprojecttreeisthemainprojectareaoftheProject Managerwin-

dow.Thesetwoterms(projecttreeandProject Managerwindow)andmaybeusedinterchangeablyinthisguide.

Proceduresarepresentedasnumberedlists.Asinglebulletindicates

thattheprocedurehasonlyonestep.

Boldtypeisusedforthefollowing:

- Keyboard entries that should be typed in their entirety exactly asshown. For example, copy file1 means to type the word copy, totype a space, and then to type file1.

- On-screen prompts and messages, names of options and text boxes,

and menu commands. Menu commands are often separated by car-

ats. For example, click Maxwell>Excitations>Assign>Voltage.- Labeled keys on the computer keyboard. For example, Press

Enter means to press the key labeled Enter. Menucommandsareoftenseparatedbythe>symbol.Forexample,

ClickFile>Exit. Italictypeisusedforthefollowing:

- Emphasis.

- The titles of publications.

- Keyboard entries when a name or a variable must be typed in place

of the words in italics. For example, copy file name means totype the word copy, to type a space, and then to type a file name.

Theplussign(+)isusedbetweenkeyboardkeystoindicatethatyou

shouldpressthekeysatthesametime.Forexample,PressShift+F1meanstopresstheShiftkeyandtheF1keyatthesametime.

Toolbarbuttonsserveasshortcutsforexecutingcommands.Toolbar

buttonsaredisplayedafterthecommandtheyexecute.Forexample,

OntheDrawmenu,clickLine meansthatyoucanalsoclicktheDraw LinetoolbarbuttontoexecutetheLinecommand.

Alternatemethodsortipsarelistedintheleft

margininblueitalic

text.

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iv


Getting HelpAnsoftTechnicalSupport

TocontactAnsofttechnicalsupportstaffinyourgeographicalarea,pleaselogontotheAnsoftcorporatewebsite,http://www.ansoft.com,clicktheContactbutton,andthenclickSupport.Youwillfindphonenumbersande-mailaddressesforthetechnicalsupportstaff.YourAnsoftaccountman-

agermayalsobecontactedinordertoobtainthisinformation.

AllAnsoftsoftwarefilesareASCIItextandcanbesentconvenientlybye-

mail.Whenreportingdifficulties,itisextremelyhelpfultoincludespecific

informationaboutwhatstepsweretakenorwhatstagesthesimulationreached.Thisallowsmorerapidandeffectivedebugging.

Context-SensitiveHelp

ToaccessonlinehelpfromtheMaxwelluserinterface,dooneofthefol-lowing:

ToopenahelptopicaboutaspecificMaxwellmenucommand,press

Shift+F1,andthenclickthecommandortoolbaricon. ToopenahelptopicaboutaspecificMaxwelldialogbox,openthedia-

logbox,andthenpressF1.
http://www.ansoft.com/http://www.ansoft.com/

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Contents-1

Table of Contents

1. IntroductionSettingUpDesigns .............................. 1-3

AbouttheDesign................................ 1-42. Setting Up the DesignOpenMaxwellandSaveaNewProject .............. 2-2

SpecifyaSolutionType ........................... 2-4

SettheDrawingUnits ............................ 2-4

3. Creating the Geometry ModelCreatetheOuterArmatureObject................... 3-2CreatetheInnerArmatureObject ................... 3-6

CreatetheCoils ................................. 3-8

Movethecoilintothefinalposition: .................3-9

Createamirrorduplicateofthecoil: .................3-9

CreatetheCoilTerminals ......................... 3-9

CreatetheBackground(Region).................... 3-9

FinalizetheGeometry............................ 3-10

4. Defining Material Properties, Excitations, andMesh OperationsDefineMaterialProperties ......................... 4-2

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Contents-2

DefinetheNonlinearMaterialfortheTwoArmatures ... 4-2

AssignMaterialProperties ........................ 4-3

AssignExcitations ............................... 4-4SetUptheExternalCircuit ........................4-5

SetUpMeshOperations.......................... 4-9

SpecifytheEddyEffectCalculation .................4-9

5. Setting Up and Running the AnalysisSetuptheAnalysis .............................. 5-2

RunningtheAnalysis ............................. 5-26. Post Processing the ResultsPlottheMagneticFluxDensityVector ............... 6-2

7. Including Motion in the SimulationAddMotion ..................................... 6-2

AddaBandObjecttotheDesign................... 6-2PostProcesstheTransientResults ................. 6-4

ClosetheProjectandExitMaxwell .................. 6-8

8. Appendix: Understanding the Maxwell InterfaceA.DesktopWindows.............................. 6-2

B.UsingMouseButtons .......................... 6-2

C.Geometry .................................... 6-3

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Introduction 1-1

1Introduction

Maxwell 3D is an interactive software package that uses finite ele-

ment analysis (FEA) to simulate (solve) electromagnetic field prob-

lems. Maxwell integrates with other Ansoft software packages to

perform complex tasks while remaining simple to use.The following types of solutions are supported by Maxwell 3D:

Electric3Dfields,whichcanbeoneofthefollowingtwocategories: Electrostatic3Dfieldscausedbyuser-specifieddistributionof

voltagesandcharges;additionalcomputedquantitiesinclude

torque,force,capacitancesasindicatedbytheuser.

Electric3Dfieldsinconductorscharacterizedbyaspatialdistri-

butionofvoltage,electricfieldandcurrentdensity;additionalquantityinthiscaseispowerloss.

Magnetostaticlinearandnon-linear3Dfieldscausedbyuser-spec-ifieddistributionofDCcurrentdensity,permanentorexternally

appliedmagneticfields;additionalcomputedquantitiesinclude

torque,force,inductances(selfandmutual)asindicatedbythe

user;

Harmonic(sinusoidalvariationintime)steadystatemagneticfieldswithpulsation-inducededdycurrentsinmassive(solid)conductorscausedbyauserspecifieddistributionofACcurrents(allwith

samefrequencybutwithpossiblydifferentinitialphaseangles)or

byexternallyappliedmagneticfields;thisisafullwavesolution

andincludeselectromagneticwaveradiation;

Estimatedtimeto

completethisguide:

45minutes.

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1-2 Introduction

Transient(timedomain)magneticfieldscausedbypermanentmagnets,conductorsandwindingssuppliedbyvoltageand/orcur-

rentsourceswitharbitraryvariationasfunctionsoftime;rotational

ortranslationalmotioneffectscanbeincludedinthesimulation.The application described in this getting started guide is an extension

ofTEAMWorkshopProblem24, which is a rotational actuatordesign.

Results presented correspond to the simulation of a 3D electromag-

netic time-transient problem with effects of large motion included in

the simulation. Both the rotor and the stator are made of solid ferro-

magnetic steel, creating significant eddy current effects. A nonlinearB-H curve for the stator and rotor steel is considered. Estimated

mechanical inertia of the rotor is included in the solution. The results

of the simulation with different FEM code are presented in IEEE

Transactions on Magnetics, Vol 38, No. 2, March 2002, pp 609-612.

By following the steps in this guide, you will learn how to perform the

following tasks:

Drawageometricmodel. Modifyamodelsdesignparameters.

Assignvariablestoamodelsdesignparameters. Specifysolutionsettingsforadesign. Validateadesignssetup. RunaMaxwellsimulation. Plotthemagneticfluxdensityvector. Runaparametricanalysis.

Seetheonlinehelp

aboutthespecific

parameteryouwantto

varytodetermineifit

canbeassigneda

variable.

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Introduction 1-3

Setting Up DesignsInMaxwell11,youarenolongerrequiredtofollowaspecificorderwhen

settingupyourMaxwelldesign.However,thefollowingorderisrecom-mended,particularlyfornewMaxwellusers:

1 OpenMaxwell,andsaveanewproject.

2 Drawthegeometryofthemodel.

3 (Optional)Ifnecessary,modifythemodel'sdesignparameters.

4 Assignvariablestodesignparameters.

5 Specifysolutionsettings.

6 RunaMaxwellsimulation.7 Createpost-processingplots.

8 Createaparametricanalysis.

9 Createafieldanimationoftheparametricanalysisresults.

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1-4 Introduction

About the DesignThegeometryfortheTEAMWorkshopProblem24rotationalactuatoris

shownbelow.

Theouterpartconsistsofaferromagneticnonlineararmaturecarryingtwo

coils.Theinnerpartiscomposedofthesamenonlinearmaterialandcanrotatearoundanaxis.Theinnerandouterpartsofthedeviceareco-axial.

Thefielddistributionisexpectedtocausethefluxdensitytoaconcentrate

inthetwosteelarmaturesintheregionswherethedistancebetweenthem

isminimal.Theexpectededgeeffectwillthenfurtherincreasethefield

concentration.Thetorqueactingontheinnerarmatureandtheflunklink-

ageofthetwocoilswillalsobecomputedinthisexample.

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Setting Up the Design 2-1

2Setting Up the Design

Inthischapteryouwillcompletethefollowingtasks:

Openandsaveanewproject. InsertanewMaxwelldesignintotheproject. Selectasolutiontypefortheproject. Setthedrawingunitsforthedesign.

Estimatedtimetocompletethischapter:

2minutes.

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2-2 Setting Up the Design

Open Maxwell and Save a New ProjectAprojectisacollectionofoneormoredesignsthatissavedinasingle

*.mxwlfile.AnewprojectisautomaticallycreatedwhenMaxwellislaunched.OpenMaxwell,addanewdesign,andsavethedefaultproject

withanewname.

1 Double-clicktheMaxwell11icononyourdesktoptolaunchMaxwell.

2 ClickProject>Insert Maxwell Design .ThenewdesignislistedintheprojecttreeandisnamedMaxwellMod-elnbydefault.The3D Modeler windowappearstotherightoftheProjectManager.

3 ClickFile>Save As.TheSave Aswindowappears.

4 Locateandselectthefolderinwhichyouwanttosavetheproject

5 TypeRotational_actuatorintheFile namebox,andclickSave.

Note IfyouhavealreadycompletedthemagnetostaticexampleintheGetting

StartedwithMaxwell:DesigningaRotationalActuatorguide,youcan

opentheexistingRotational_actuatorprojectratherthancreatinganewone.

Tosaveyourproject

frequently,click

File>Save..

Thecurrentdesignhasthedefaultname

MaxwellModel1listedin

theProjectManagerwin-

dow.Youcanchangeit

byright-clickingit,select-

ingRenamecommand,andenteringanewname

forit.Youcanaddaddi-

tionaldesignstothe

projectbyrepeatingstep2above,orbyclickingthe

correspondingicononthe

toolbar.Forthecurrent

simulationtask,wedonot

needtocreateadditional

designs.

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Setting Up the Design 2-3

Theprojectissavedinthespecifiedfolderunderthename

Rotational_actuator.mxwl.

Note ThecurrentdesignhasthedefaultnameMaxwellModel1 listedintheProject Manager window.Youcanchangeitbyright-clickingit,selectingRename,andenteringanewname.Youcanaddadditionaldesignstotheprojectbyrepeatingstep2aboveorbyclickingthecorresponding

icononthetoolbar.Forthissimulationexample,wedonotneedtocreate

additionaldesigns.

Project Manager

Window

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2-4 Setting Up the Design

Specify a Solution TypeAsmentionedintheintroductiontothisgettingstartedguidemultipletypes

ofMaxwell3Dsolutionsarepossibletochoosefromdependingonthespecificapplication.ForthisdesignchooseaTransienttypeofsolution.

1 ClickMaxwell>Solution Type fromthemenus.TheSolution Typedialogboxappears.

2 SelectTransient.3 ClickOK.Set the Drawing Units1 Click3D Modeler>Units.

TheSet Model Unitsdialogboxappears.2 SelectmmfromtheSelect unitspulldownmenu.3 ClickOK.

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Creating the Geometry Model 3-1

3Creating the GeometryModel


Createtheouterarmatureoftheactuatorbysubtractingandunitingobjects.

Createtheinnerarmatureoftheactuator. Createthecoils. Createthecoilterminals. Createthebackgroundobject.

Estimatedtimeto

completethischapter:

40minutes.

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3-2 Creating the Geometry Model

Create the Outer Armature ObjectBeforecreatingtheoutercylinder,makesurethattheXYdrawingplaneis

selectedandthat3Disselectedasthemovementmode.

Tocreatetheoutercylinder:

1 ClickDraw>Cylinderfromthemenus.Thecursorchangestoasmallblackbox(Drawingmode).

2 Selectthecenterofthecylinderbyclickingatthe(0,0,0)location(theoriginofthecoordinatesystem).

3 Enter104.5fortheradiusinthedXbox(atthebottomofthescreen),andclickEnter.

4 Enter25.4fortheheightinthedZbox,andclickEnter.ThePropertieswindowappearsautomatically,withtheAttributetabdisplayed.

Youcanalsoaccessthepropertieswindowdirectlyfromanareainthe

Maxwelldesktop.

5 ClickOK.

6 ChangetheNamefieldvalue(currentlyCylinder1)toOuter_arm.7 Tochangethecolorofthecylindertored:

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a.ScrolldowntotheColorproperty,andclicktheEditbutton.TheColorpalettewindowappears.

b.SelectoneoftheredshadesfromtheBasiccolorsgroup,andclick

OKtoreturntothemainPropertieswindow.8 Tosetthetransparencyto0.6,clickthebuttonfortheTransparent

property,andenter0.6inthebox,andclickOKtoclosetheSet Trans-parency dialogboxandreturntothemainPropertieswindow.9 ClickOKtoclosethePropertieswindow.10 Inthehistorytreewindow,double-clicktheCreateCylinderfield.

ThePropertieswindowappears,withtheCommandtabdisplayed.11 Inthiswindow,youcanvisualizethegeometricdataandeditit.ClickOKwhenyouaredonemakinganydesirededits.Repeattheprocedureabovetocreateanothercylinder(namedCylinder_tool)withthesamecenterandheightasOuter_armbutwitharadiusof83.1 mm.Next,subtractCylinder_toolfromOuter_arm.

Tosubtractthesecondcylinderfromthefirst:

1 Selectbothcylindersbyclickingtheirnamesinthehistorytree(holdtheCtrlkeydownwhenselectingthesecondone).

2 Click3D Modeler>Boolean>Subtract.3 Ifnecessary,movetheOuter_armobjectintotheBlank Partscolumn

andtheCylinder_toolobjectintotheTool Partscolumn,byselectingeachobjectandusingthearrowstomoveit.

4 ClickOK.Addthetwomagneticpolestotheouterarmature.Firstcreateabox,then

movetheboxintothecorrectposition,andusetheMirrorcommandtocre-

ateaduplicateofthebox.Unitethethreemodelobjects,andsubtractthe

acylindertoarriveatthefinalshape.

Tocreateabox:

1 SelectBoxfromtheDrawmenu.2 Entertheboxposition(-13.0, 0, 0)intheX,Y,andZfieldsatthebot-

tomofthescreen,andthenpressEnter.3 Entertheboxsize(27.8, -40, 25.4)inthedX,dY,dZfields,andthen

pressEnter.ThePropertieswindowappears.

4 ClickOK.

ALinear stepsweeptypeenablesyouto

specifyalinearrange

ofvalueswitha

constantstepsize.

UsetheTabkeytonavigatebetween

valuefields(fromXto

YtoZandfromdXto

dYtodZ).

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Tomovetheboxintoposition:

1 Selecttheboxobjectpreviouslycreated(forexample,clicktherespec-

tivenameinthehistorytreewindow).

2 SelectEdit>Arrange>Move.3 Enter(0, 0, 0)inthe (X, Y, Z) fieldsastheoriginofthemovevector,

andpressEnter.4 Enter(0, -45, 0)inthe(dX, dY, dZ)fieldsasthetargetpointofthe

movevector,andpressEnter.Tocreateaduplicateoftheboxusingmirroring:

1 Selecttheboxpreviouslycreated.

2 SelectEdit>Duplicate>Mirror.3 Enter(0, 0, 0)inthe(X, Y, Z)fieldsascoordinatesfortheanchorpoint

onthemirrorplaneandpressEnter.4 Enter (0, 1, 0)inthe(dX, dY, dZ) fieldsascoordinatesoftargetpointof

thevectornormaltothemirrorplaneandpressEnter.Tounitethethreeobjectsinthemodel:

1Selectthethreeobjectsinthemodelfromthehistorytreewindow(selectOuter_armfirst,thenholddowntheCtrlkeyandselecttheboxes).

2 Select3D Modeler>Boolean>Unite.BecausethefirstselectedobjectwasOuter_arm,thefinalobjectname

assignedbydefaultisOuter_arm.Thenameoftheobjectscanbeeasily

changedifdesiredinthePropertieswindowwiththeAttributetabselected.Toprovidethefinalshapeforthemagneticpolefaces:

1 Createacylinderwiththecenterat(0, 0,0),aradiusof53.75,andaheightof25.4.

2 SelecttheOuter_armobject,thenholddowntheCtrlkeyandselectthecylinder.

3 Select3D Modeler>Boolean>Subtract.TheSubtractdialogboxappears.

4MakesuretheOuter_armobjectisintheBlank Parts columnandtheCylinder1objectisintheTool Parts column.

5 ClickOK.

Formoreinformation

abouttheotheroptions

intheSetup SweepAnalysisdialogbox,seethe

onlinehelp.

Viewthedesign

variationsthatwillbe

solvedintableformat

undertheTabletab.Thisenablesyouto

visualizethedesign

variationsthatwillbe

solvedandmanually

adjustsweeppointsif

necessary.

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TheOuter_armobjectshouldlookasshownbelow.

Toautomatically

expandtheprojecttree

whenanitemisadded

totheproject:Click

Tools>Options>Gen-eral Options.UnderProject Options,selectExpand ProjectTree on Insert.

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Create the Inner Armature ObjectTodrawtheinnerarmature:

1Createacylindernamedshaft,withthecenterat(0, 0, 0),aradiusof25.4mm,andanaxiallengthof25.4mm.

2 Createacylindernamed Inner_arm,withthecenterat(0,0,0),aradiusof38.1mm,andanaxiallengthof25.4mm.

3 SelectInner_arm,andthenholddowntheCtrlkeyandselectshaft.4 Select3D Modeler>Boolean>Subtractfromthemenubar.

TheSubtractdialogboxappears.5

MakesuretheInner_arm objectislistedintheBlank PartscolumnandtheshaftobjectislistedintheTool Partscolumn.6 ClickOK.Changethecolorandtransparencyofthenewlycreatedobjectasdesired.

Addthetwomagneticpolestotheinnerarmature.Firstcreateabox,then

movetheboxintothecorrectposition,andusetheMirrorcommandtocre-

ateaduplicateofthebox.Unitetheinnerarmaturewiththetwoboxes,and

intersectitwithacylindertoarriveatthefinalshape.Tocreateabox:

1 SelectBoxfromtheDrawmenu.2 Entertheboxposition(-12.7, 0, 0)usingtheX,Y,Zfieldsatthebottom

ofthescreen(navigatewiththeTabkeyfromtheXfieldtotheYfieldtotheZfield),andpressEnter.

3 Entertheboxsize (25.4, -20, 25.4)usingthedX,dY,dZvaluefields,andpressEnter.ThePropertieswindowappears.

4 ClickOKtovalidate.Tomovetheboxintoposition:

1 Selecttheboxobjectpreviouslycreated(forexample,clicktherespec-

tivenameinthehistorytreewindow).

2 SelectEdit>Arrange>Move.3 Specify(0, 0, 0)inthe (X, Y, Z)fieldsastheoriginofthemovevector,

andpressEnter.4 Specify(0, -35, 0) inthe(dX, dY, dZ) fieldsasthetargetpointofthe

movevector,andpressEnter.Tocreateaduplicateoftheboxusingmirroring:

1 Selecttheboxpreviouslycreated.

2 SelectEdit>Duplicate>Mirror.

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3 Enter (0, 0, 0) inthe(X, Y, Z)fieldsascoordinatesfortheanchorpointonthemirrorplane,andpressEnter.

4 Enter(0, 1, 0) inthe(dX, dY, dZ)fieldsascoordinatesoftargetpointofthevectornormaltothemirrorplane,andpressEnter.

Tounitetheinnerarmatureobjectwiththetwoboxes:

1 Selectthethreeobjectsinthemodelfromthehistorytreewindow

(selectInner_armfirst,thenholddowntheCtrlkeyandselectthetwoboxes).

2 Select3D Modeler>Boolean>Unitefromthemenubar.BecausethefirstselectedobjectwasInner_arm,thefinalobjectname

assignedbydefaultisInner_arm.ThenameoftheobjectscanbeeasilychangedinthePropertieswindowontheAttributetab.Toprovidethefinalshapeforthemagneticpolefaces:

1 Createacylinderwiththecenterat(0, 0,0),aradiusof51.05,andaheightof25.4.

2 SelecttheInner_arm object,andthenholddowntheCtrlkey,andselectthenewCylinder2object.

3 Select3D Modeler>Boolean>Intersect.

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Create the CoilsFirstcreateanewcoordinatesystem(CS1)suchthatinthenewcoordi-

natesystemtheXYplanebecomesamedianplaneofthemodel.

Tocreatethenewcoordinatesystem:

1 SelectCoordinate System>Create>Relative CS>Offsetfromthe3DModelermenu.2 Entertheneworigin(0, 0, 12.7)inthe (X, Y, Z)boxes,andthenpressEnter.Thecoil(s)arecreatedbysweepingthecoilcross-sectionalongapath.

Dothefollowingtocreatethepath,thecross-section,andthecoil:1 SetthedrawingplanetoXZ.2 SelectRectanglefromtheDrawmenu.3 Enter(-17, 0 -15.5) inthe(X, Y, Z)boxes,fortherectangleposition,

andthenpressEnter.4 Enter(34, 0, 31)inthe (dX, dY, dZ)boxes,andpressEnter.5 SelecttheEdit>Select>Faces,andselectthenewlycreatedrectangle

byclickingonitinthe3DModelerwindow.6 Select3D Modeler>Surface>Uncover Faces.7 Changethenameoftheuncoveredentityto path.8 SetthedrawingplanetoYZ.9 SelectRectanglefromtheDrawmenutodrawthecross-sectionofthe

coil.

10 Enter(0, 0, 15.5)inthe (X, Y, Z)boxes,fortherectangleposition,andthenpressEnter.

11 Enter (0, 17, 24) inthe (dX, dY, dZ)boxes,andpressEnter.12 Changethenameofthenewlycreatedrectangleto coil1.13 Selectthepathandthecross-sectionbyselectingtheirnamesinthe

historytreewindow(holddowntheCtrlkeyforthesecondselection).14 SelectSweep>Along PathfromtheDrawmenu,andclickOKto

acceptthedefaults.

15 ClickOKtocreatethecoilThefinalcoilshapehasroundedoutsidecorners.

UsingthenewcoordinatesystemCS1,dothefollowingtoachievethefinalshape:

1 Createacylinderattheoriginwitharadiusof43mmandaheightof

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17mm.2 Selectthecylinderandthecoil,andperformaBooleanintersection.Movethecoilintothefinalposition:1 Selectthecoilbyclickingitsnameinthehistorytreewindow.

2 SelectArrange>Move fromtheEditmenu.3 Specify(0, 0, 0)inthe(X, Y, Z) fields,fortheoriginofthemovevector,

andthenpressEnter.4 Specify (0, 54.5, 0)inthe(dX, dY, dZ)fieldsasthetargetpointofthe

movevector,andpressEnter.Createamirrorduplicateofthecoil:

1 Selectthecoilbyclickingitsnameinthehistorytreewindow.

2 SelectArrange>MovefromtheEditmenu.3 Specify(0, 0, 0) inthe(X, Y, Z)fieldsasthecoordinatesoftheanchor

pointonthemirrorplane,andthenpressEnter.4 Specify(0, 1, 0)inthe(dX, dY, dZ)fieldsascoordinatesoftargetpoint

ofthevectornormaltothemirrorplane,andpressEnter.Create the Coil TerminalsTocreatetheterminalsforthecoils:

1 Selectthetwocoilsbyclickingtheirnamesinthehistorytreewindow.

2 SelectSurface>Sectionfromthe3D Modelermenu,specifyXYasthesectionplane,andclickOK.

3 SelectBoolean>Separate Bodiesfromthe3D Modelermenu.Thisallowstheseparationoftheinter-linkedsheetobjectscreatedsincetheintersectionoftheXYplanewitheithercoilcreatedtwoterminalsin

eachcoil.

4 Selectthetworedundantterminals,oneatatime(clickeachnamein

thehistorytreewindow),andthenpresstheDeletekeyonthekey-board.

Create the Background (Region)Definearegionboxwiththeoriginat(-250,-250,-250)andthedimen-

sions(500,500,500).

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Finalize the GeometryTofinalizethegeometry:

1 SelecttheInner_armobject.2 Rotateit(usetheArrange>RotatecommandontheEditmenu),speci-

fyingtheZ axisintheglobalcoordinatesystem,andanangleof +29.5degrees).

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Defining Material Properties, Excitations, and Mesh

4 Defining MaterialProperties, Excitations,and Mesh Operations


Definematerialproperties. Assignexcitations. Setupthemeshoperations.

Estimatedtimetocompletethischapter:

15minutes.

G tti St t d ith M ll T i t P bl

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4-2 Defining Material Properties, Excitations, and

Define Material PropertiesInthePropertieswindowwiththeAttributetabselected,materialproper-tiesarealreadypresent,withadefaultproperty(vacuum)already

assignedtoobjects.Youcanchangethematerialpropertyofanyobjectassoonastheobjectisdefined.Instead,inthisguide,youwillgroupallmate-

rialdefinitionandassignmenttogether.

DefinetheNonlinearMaterialfortheTwoArmatures

Todefinethenonlinearmaterialtobeusedforthearmatures,dothefol-

lowing:

1 SelecttheOuter_arm objectbyclickingonitsnameinthehistorytreewindow.

2 MakesuretheAttributetabisselected.3 IntheMaterialrow,clickthevaluefieldintheValuecolumn.4 IntheSelect Definitionswindow,clicktheAdd Materialbutton.5 Enterarm_steel intheMaterial Namebox.6 IntheRelative PermeabilityrowandtheTypecolumn,clickthecorre-

spondingcheckbox,andchangethetypefrom SimpletoNonlinear.7 SelecttheBH CurvefieldintheValuecolumn.8 Appendadditionalrowstothetableasneeded,andentertheHandB

datafromthetablebelowintherespectivecolumns.

H(A/m) B(T)

1. 0 0

2. 4000 1.413

3. 8010 1.594

4. 16010 1.751

5. 24020 1.839

6. 32030 1.896

7. 40030 1.9368. 48040 1.967

9. 64050 2.008

10. 80070 2.042

11. 96080 2.073


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9 ClickOKwhendoneenteringtheHandBvalues.10 ClickValidate,andthenclickOKtoexittheEditoperation.11 ClickOKoncemoretovalidatethedefinitionandclosethe Select Def-initionswindow.AssignMaterialProperties

SelecttheInner_armobject,andassignthenewlydefinedarm_steelprop-

erty.Selectthetwocoils,andassigncopperasthematerialproperty:

Toassignthematerialpropertiestothemodelobjects:

1 Selecttheobjectbyclickingitsnameinthehistorytreewindow.

2 MakesuretheAttributetabisselected.3 IntheMaterialrow,clickthefieldintheValuecolumn.4 Scrollthroughthelibrary,andselectthedesiredmaterialproperty.5 ClickOKtoassignthematerialandclosethewindow.6 Leavethematerialassignmentfortheregion(background)

unchanged.

12. 112100 2.101

13. 128110 2.127

14. 144120 2.15115. 176150 2.197

16. 272230 2.24

17. 272230 2.325

18. 304260 2.37

19. 336290 2.42

20. 396000 2.5


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Assign ExcitationsCurrentsneedtobedefinedandassignedasexcitationsforthetwocoil

terminals.

Todefinethecurrents:

1 Selecteachterminal(oneatatime)byclickingitinthehistorytreewin-

dow.

2 Right-click,andselectAssign Excitation>Coil Terminalfromtheshort-cutmenu.

3 Enter350 AintheNumber of Conductorsbox.4 Optionally,youcanswapdirection.

5 ClickOKtovalidatetheexcitationandclosethewindow.6 Repeatsteps1-6forthesecondterminal,makingsurethatthetwoter-

minalcoilsareconnectedinseries.

Bydefault,allfacesoftheregionbox(background)areassignedwithmag-

neticfluxtangentboundaryconditions.Therefore,noadditionalboundary

conditionsarerequiredforthisexampleproblem.

Toaddawinding:1 Right-clickinthemodelwindow,andselectAssign Excitation>AddWinding.

TheWinding Definitionwindowappears.2 EnteranameintheNamebox(oracceptthedefault,suchasWinding1).3 SettheTypetoExternal,andselecttheStrandedradiobutton.4

LeavetheInitial Currentsetatthedefaultvalueof0(zero).

5 ClickOK.Toaddaterminalforthewinding:

1 Right-clicktheWinding1nameintheprojecttree,andthenselectAddterminals.2 Selectthetwopreviouslydefinedterminalsbyclickingontheirnames

(whileholdingdowntheShiftkey).3 ClickOK.

Intheprojecttree,thetwoterminalsaremovedbeneathWinding1.

Note Inthisapplicationweareusinganexternalcircuittosupplytheexcitation

tothecoil.Forthisexample,wealsocouldhaveusedavoltagetypeofexcitation.


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Theregionbox(background)willhavebydefaultallfacesassignedwith

magneticfluxtangentboundaryconditions.Thusforthisproblemnoaddi-

tionalboundaryconditionsareneeded.

SetUptheExternalCircuitThedrivingcircuitforthewindinginthisdesignconsistsofavoltage

sourceinserieswitharesistorandwiththewinding.Whencomplete,the

circuitshouldlooksimilartothefigurebelow.

Tosetuptheexternalcircuit:

1 FromtheWindowstaskbar,clickStart>Ansoft>Maxwell>Maxwell Cir-cuit Editor.TheMaxwellCircuitEditoropens.

2 ClickProject>Insert Maxwell Circuit Design.


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g


Thecircuitsheetappears.

3 SelecttheComponentstabintheprojecttreewindow.4 Addthecircuitelements:

a.Placethewindingelementonthesheet:Intheprojecttree,underMaxwell Circuit Elements/Dedicated Elements,selecttheWindingelement,anddragitontothesheetatthedesiredlocation.Right-

click,andselectFinishtoplacethecomponent.Toviewtheproper-ties,clickthecomponentintheschematicwindow.InPropertieswindow,changetheDeviceNametoWinding1,thesamenameyouusedwhendefiningthewindingintheMaxwelldesign.ClickDraw>Rotatetopositionthewindingvertically.

b.Placearesistoronthesheet:Intheprojecttree,underPassive Ele-ments,selectResistor,anddragtheresistorontothesheet.Right-click,andchooseFinishtoplaceitwheredesired.Double-clickthesymboloftheresistor,andchangethevalueoftheresistor,R,to

Note Intheschematicsheet,allthewindingsmustusethesamenamesthatweredefinedfortheminMaxwellintheprevioussection.


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3.09 Ohms.ClickOKwhendone.c.Placeavoltagepulse:Intheprojecttree,underSourcesselectaVPulseelement(PulseVoltageSource),dragittothesheet,andthenright-clickandselectFinishtoplaceitontothesheet.Double-clickthesourceelementsymbolonthesheet,andthenspecifythe

characteristicsofthesourceasfollows:

V1(Initialvoltage)=0

V2(Peakvoltage)=5.97

Tr(Risetime)=0.001

Tf(Falltime)=0.001

Pw(Pulsewidth)=1

Period=1

Leavetheotherfieldssettothedefaultvalues,andclickOK.

5 Connectthecircuitelementsinseries:

a.ClickDraw>Wire.b.Clicktherespectiveterminals.

c.Whendone,placetheGroundsymbol:ClickDraw>Ground(orclicktheGroundsymbolonthetoolbar),placetheGroundsymbolonthesheetinaconvenientlocation,right-click,andselect Finishtoplacethesymbol.

d.Toconnectthenthegroundtothecircuit,clickDraw>Wire,anddrawthefinalwire.


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6 Exportthenetlist:

a.ClickMaxwell Circuit>Browse Netlist.b.ClickNetlist>Export.TheNetlist Exportdialogboxappears.

c.Selectthefolderwhereyouwanttosavetheexternalcircuitfile.

d.Typetrans_circ.sphintheFile namebox.e.ClickSave.

7 ClickFile>Save,typeaname,andclickSavetosavetheMaxwellCir-cuitEditorproject.

8 ClickFile>Exit toclosetheMaxwellCircuitEditorprogram.9 InMaxwell(whichshouldstillbeopen),assigntheexternalcircuit:

a.ClickMaxwell>Excitations>External Circuit>Edit External Circuit.The Edit External Circuitdialogboxappears.

b.ClickImport Circuit.TheSelect Filedialogboxappears.

c.SetDesigner Net List Files (*.sph)fromtheFiles of typepull-downlist.

d.Browsetothelocationwhereyousavedthecircuit,selectit,and

clickOpentoimportit.10 ClickOKtocloseanyopendialogboxes.


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Set Up Mesh OperationsThisexampleinvolvestransientmagneticfieldsinthepresenceofmassive

(solid)conductors,creatingeddycurrents.Tocatchtheeffectswithrea-

sonableaccuracy,afinermeshisrequiredinthoseobjectsbecauseskineffectsarepartofanaccuratetransientsolution.

ToseedthemeshtothedesireddensityintheOuter_armandInner_armobjects:

1 Selectthetwoobjectsfromthehistorytreewindow.

2 Right-clickinthe3DModelerwindow,andselectAssign Mesh Opera-tion>Inside Selection>Length Based.TheElementLengthBasedRefinementdialogboxappears.

3 Enter10intheMaximum Length of Elementsbox,andselectmmastheunits.

4 LeavetheRestrict the Number of Elements checkboxcleared.5 ClickOK.Thisoperationwillrefinethemeshatrun-timebeforethetransientproblem

solutionbegins.Thismeshwillbeusedforalltimesteps;therefore,the

meshdensityshouldbeappropriatefortheanticipatedfieldbehaviorfortheentiretransientanalysis.

SpecifytheEddyEffectCalculation

Eddyeffectscanbecalculatedinobjectswithnonzeroelectricconductiv-

ity.

Tocalculateeddyeffects:

1 ClickMaxwell>Excitations>Set Eddy Effects.


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TheSet Eddy Effect dialogboxappears.2 SelectthecheckboxesfortheInner_armandOuter_armobjects.

3 ClickOK.

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Setting Up and Running the Analysis 5-1

5 Setting Up and Running theAnalysis


Setuptheanalysis. Runandsolvetheanalysis.

Estimatedtimeto


20minutes.


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5-2 Setting Up and Running the Analysis

Set up the AnalysisTosetuptheanalysis:

1 Right-clicktheAnalysisfieldintheprojecttree.Ashortcutmenuappears.

2 SelectAdd Solution Setup.TheSolve Setup dialogboxappears.

3 ClicktheGeneraltab.4 Type 0.04 intheStop time box,andselectsastheunits.5 Type0.005intheTime stepbox,andselectsastheunits.6 Toaddasweep:

a.ClicktheSave Fieldstab.b.SelectLinear StepfromtheTypepull-downlisttoidentifythetypeofsweep.

c.Type 0.001intheStartbox.d.Type0.056intheStopbox.e.Type 0.005 intheStep Sizebox.f.ClickAdd Sweep.

7 ClickOK.Running the AnalysisToruntheanalysis:

Right-clicktheAnalysisfieldintheprojecttree,andselectAnalyze.Oncetheanalysisiscomplete,youcanmoveontothepostprocessing.

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Post Processing the Results 6-1

6 Post Processing theResults


Plotthemagneticfluxdensityvector. ClosetheprojectandexitMaxwell.

Estimatedtimeto


15minutes.


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6-2 Post Processing the Results

Plot the Magnetic Flux Density VectorPlotthefluxdensityvectoronthemid-verticalsymmetryplaneofthe

device.Youshouldalreadyhavearelativecoordinatesystem(CS1)con-

tainingthedesiredplotplaneasacoordinatesystemplane.Topreparefortheplot,createalistofobjects(sincewewanttherespec-

tiveresultsplottedinthetwoarmaturesonly):

1 Select(byclickinginthehistorytreewindow)theOuter_armandInner_arm objects.2 Click3D Modeler>List>Create>Object List.

Thelistofselectedobjects(Objectlist1)isaddedundertheListsinthe

historytreewindow.Tosetthetimestepforpostprocessing:

1 ClickView>Set Solutions Context.TheSet View Contextdialogboxappears.

2 SelectthedesiredsolutionsetupfromtheSolution Name pull-downlist.

3 SelectatimestepfromtheTimepull-downlist.4 ClickOK.Toperformtheplot,followthesesteps:

1 ChangetherenderingofbothOuter_armandInner_armtowireframe.

2 SelecttheRelativeCS1:XYplaneunderPlanesinthehistorytreewin-dow.

3 Right-clickField Overlaysintheprojectmanagementwindow,andselectFields>B>B_Vector.

4 MakesuretheQuantityisB_Vector.5 IntheVolumecolumn,clickObjectlist1.6 ClickDone.7 Double-clickthelegend.

8 ClicktheScale,Marker>Arrow,orPlotstabsifyouneedtochangethescale,thesizeorspacingofthearrows.

Asrequested,Max-

wellhasmodifiedthe

T-junctiongeometryso

thatthevalueofoffset

is0.09inches,orthe

optimalvariablevalue.

Youcanselectadiffer-

entvalueofoffsetinthetable,andthen

clickApplytomodifytheT-junctiongeome-

trytothatoffsetvalue.

Whenyouaredone,

clickReverttoreturnthegeometrytothe

optimalvalue.


The plot should look similar to the figure below:

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Theplotshouldlooksimilartothefigurebelow:

ToplotthecurrentdensitydistributiononthesameXPplaneofCS1:

1 Selecttheplane,right-clickinthe3Dmodelerwindow,andselectFields/J/Mag_J.2 SpecifythevolumeasOuter_arm.3 ClickDonetoplot.Noticethepartialpenetrationofthefieldinthestatorofthedevice;the

transientdistributionofthecurrentdensityshowssignificantskineffects.

Varyingglobalquantitiesasafunctionoftimeisaveryimportantoutputfromthetransientanalysis.Examplesofsuchquantitiesofinterestinclude

currentsandvoltages,powerloss,torque/force,fluxlinkageofwindings,andinducedvoltages.


To create those plots:

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Tocreatethoseplots:

1 Right-clickResultsintheprojecttree,andselectCreate Report.2 LeavetheReport TypesettoTransientandtheDisplay Type toRect-

angular Plot.3 ClickOK.4 FromtheSolutionpull-downlist,selectWinding1.5 FromtheCategorypull-downlist,selectCurrent.6 ClicktheAdd Tracebutton.7 ClickDonetodisplaytheplot.Tocreateaplotofthetorqueasafunctionoftime:

1 Right-clickResultsintheprojecttree,andselectCreate Report.2 LeavetheReport TypesettoTransientandtheDisplay Type toRect-angular Plot.3 ClickOK.

TheTracesdialogboxappears.4 FromtheSolutionpull-downlist,selectTorque1.5 FromtheCategorylist,selectTorque.6 ClicktheAdd Tracebutton.7 ClickDonetodisplaytheplot.


To close the plot (it will still be available to view later):

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Toclosetheplot(itwillstillbeavailabletoviewlater):

ClicktheXintheupperrightcorneroftheplotwindow.


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Including Motion in the Simulation 7-1

7 Including Motion in theSimulation


Includelargemotioninthesimulation. Postprocessthetransientresults.

Estimatedtimeto


15minutes.


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7-2 Including Motion in the Simulation

Add MotionBeforeaddingmotion,savethewithoutmotiondesignandcreateacopy:

1 Savethetransientwithoutmotiondesign.

2 Right-clickthenameofthedesignintheprojecttree,andselectCopy.3 Topasteitintothesameprojectfolder,right-clickthenameofthe

projectintheprojecttree,andselectPaste.4 Doubleclickthenameofthecopytomakeittheactivedesign.

AddaBandObjecttotheDesign

Thebandobjectisaregularpolyhedronpositionedsothatitcontainsall

rotatingobjectsinsideit.Toaddthebandobject:

1 SettheworkingcoordinatesystemtoCS1.

2 CreatearegularpolyhedronaroundtheZaxiswiththefollowingprop-

erties:

Namedband

Originat(0,0,-120)mm

Radiusof52.5mm

240mmlong

Itsendfacescoincidewiththefacesoftheregionboxcreatedat

3.5.

3 Createacylindercalledair_rotor withthefollowingproperties Originat(0,0,-120)mm

Radiusof51.05mm

240mmlong

Containstherotatingpartinside.

Assignitthematerialpropertyofvacuum.

Thebandobjecthasitscircumferencebetweentheinnerarmatureandtheouterarmatureanditcontainsinsideittheair_rotor andInner_arm objects.Makesurethebandobjectisassignedthematerialpropertyofvacuum.Tosetthebandobject:

1 Selectthebandobject.2 Right-clickModelintheprojecttree,andthenselectMotionSetup>Assign Band.

TheMotion Setupdialogboxappears.3 ClicktheTypetab.

Youcanalsousethe

Design Propertiescommandtoaddnewvariables.


4 SpecifyRotateastheMotion Type.

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5 ClicktheMechanicaltab.6 Enter0.0024 Kg m2asMoment of Inertiaand0.015 N m sec / radas

theDamping.7 ClickOK.Toapplytheappropriatemeshoperationtothebandobject:

1 Selectthebandobject.

2 Applyameshoperationrequestingthemaximummeshsizeof20mmfortherespectiveelements.

3 Toinitializetheproblem,right-clickSetup1intheprojecttree,andselectRevert to Initial Mesh.

Nowyouarereadytostarttheanalysiswiththeeffectoflargemotion

included.


Post Process the Transient Results

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Postprocessingisperformedasforthecasewithoutmotion.However,

morequantitiesareavailabletorepresentas2Dplots(asafunctionof

time)duetothemechanicalquantitiesthatarenowavailable.Thosequan-titiescanbeaddedastraceswhenyoucreatethereportifyousetthesolu-

tiontoMotion.Tocreateaplotofthepositionasafunctionoftime:

1 Right-clickResultsintheprojecttree,andselectCreate Report.2 LeavetheReport TypesettoTransientandtheDisplay TypesettoRectangular Plot.3 ClickOK.

TheTracesdialogboxappears.4 FromtheSolutionpull-downlist,selectMotion.5 FromtheCategorylist,selectPosition.6 ClicktheAdd Tracebutton.


7 ClickDonetodisplaytheplot.

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Followthesamestepstoplotthecurrent,torque,andpowerlossvs.time

(selecting a different for each plot) The resulting plots are shown

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(selectingadifferentCategoryforeachplot).Theresultingplotsareshownbelow.


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Close the Project and Exit MaxwellCongratulations!YouhavesuccessfullycompletedthisMaxwell11GettingStartedguide!YoumayclosetheprojectandexittheMaxwellsoftware.

1 ClickFile>Save tosavetheproject.2 ClickFile>Close.3 ClickFile>Exit toexitMaxwell.

8 A di U d t di

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Appendix: Understanding the Maxwell Interface 8-1

8 Appendix: Understandingthe Maxwell Interface

Inthischapteryouwilllearnhowtocompletethefollowingtasks:

Recognizedesktopwindows. Usemousebuttons. Setupamatrix.

Estimatedtimeto


15minutes.


A.Desktop Windows

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8-2 Appendix: Understanding the Maxwell Interface

B.Using Mouse ButtonsIngeneral,theleftmousebuttonisusedtoselectitems(menucommands,objects,properties,etc.).Double-clickingtheleftmousebuttononanitem

opensapropertieswindowandallowsyoutovisualizesettingsandedit

properties.Right-clickingiscontextdependentand,ingeneral,allowsyou

toperformcontext-specificoperations(suchasassigningboundarycondi-

Menu Bar Tool BarProject Manager

Window

History tree

Window

3D Modeler

Window

Progress

Window

MessageWindow


tionsorexcitations,performingfieldplotsonpreviouslyselectedgeome-

tries,orexitingthezoommodeordrammode,tonameafewexamples).

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Appendix: Understanding the Maxwell Interface 8-3

C.Geometry

209.0

50.8

102.1

107.5

27.8

21.4

12.7

25.4

Axial length (rotorand stator)= 25.4

Coils


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8-4 Appendix: Understanding the Maxwell Interface

Documents

13084219-transient