Busbar Design Guide

CircuitComponentsInc.

 BusBars CircuitComponentsInc. 2400SRooseveltStreet Tempe,Arizona85282 Tel:480-967-0624 Fax:480-967-9385 e-mail:[email protected] e-mail:[email protected] Buss ussco® o®is isa trad tradem emar ark kof of Circ Circui uittCom Compo pone nen ntsI tsInc nc..

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©200 2008 8Cir Circu cuiitCom Compo pone nent nts sInc Inc. .al all lri righ ghttsres rese erved rved..

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TABLEOFCONTENTS

A) A) ABOUTCIRCUITCOMPONENTSINC.(CCI) .................................................. .................................................................. ................ 3 B) BUSB ARBENEFITS.................................................... .............................................................................. ............................................... ..................... 3 C) COMMON BUSB AR A APPLICATIONS ................................................... ............................................................................. .......................... 4 D) ABOUTTHISDESIGNGUIDE ................................................ .......................................................................... ....................................... ............. 5 A) A) ELECTRICAL ................................................. ............................................................................ ..................................................... ................................. ....... 5 B) PHYSICAL................................................. ........................................................................... .................................................... ...................................... ............ 7 C) MECHANICAL ................................................ .......................................................................... ..................................................... .................................. ....... 8 D) ENVIRONMENTAL ................................................... ............................................................................. ................................................... ......................... 8 A) A) PRODUCTCONFIGURATIONS .................................................... .............................................................................. .................................. ........ 9 B) M ATERIALOPTIONS ................................................... ............................................................................. ............................................. ................... 10 C) TERMINATIONOPTIONS .................................................. ............................................................................ ......................................... ............... 12 D) MOUNTING OPTIONS .................................................. ............................................................................ ............................................. ................... 13 E) M ARKINGOPTIONS .................................................... .............................................................................. ............................................. ................... 13 F) TESTINGOPTIONS ................................................. ........................................................................... ................................................. ....................... 13 G)STANDARDC APABILITIESANDTOLERANCES................................................. .............................................................. ............. 14

A) A) TECHNICAL A ASSISTANCE................................................. ........................................................................... ......................................... ............... 16 B) QUALITY .................................................. ............................................................................ .................................................... .................................... .......... 16 C) CUSTOMERSERVICE .................................................. ............................................................................ ............................................. ................... 16 D) ELECTRONICD ATAFORMAT .................................................... .............................................................................. ................................ ...... 16 E) PRICING ................................................... ............................................................................. .................................................... .................................... .......... 16 F) LEADTIME .................................................... .............................................................................. .................................................... ............................... ..... 16











CCIhasover30yearsofexperiencemanufacturingBusBarsinavarietyofsizesand shapesthataddressafullrangeofelectronicdevicesandsystems.Theseinnovative andcosteffective,custom-engineeredsolutionsareavailablein andcosteffective,customengineeredsolutionsareavailableinachoiceoflaminated, achoiceoflaminated, machined,andpowder-coatedproductsdesignedtoimproveelectricalperformance, simplifysystempackaging,savespace,reducesystemcost,andimprovequalityover conventionaltechnology. Laminatedbusbarsareprecision-engineeredassembliesconsistingofalternatinglayers ofconductorandinsulator.Theycanbecustom-designedtoincludevirtuallyany connector,terminal,orinterfacemethod,while connector,terminal,or interfacemethod,whilealsoservingtocontaincir alsoservingtocontaincircuitelements cuitelements includingcapacitors,resistors,circuitbreakers,andsolid-statedevices,suchashighpowerswitchingtransistors. CCIalsoprovidesbusbardesignservicestoitscustomersthroughitsin-house EngineeringDesignGroup.Notonlycanwecreateaproduction-readydesign,wecan quicklyproduceprototypesandprovideproductionquantitiesoftested,ready-to-install busbarsystems. AtCCI,weaimtodevelopaleadposit AtCCI,weaimtodevelopaleadpositionasasupplierofpowerdi ionasasupplierofpowerdistributionsolutionsto stributionsolutionsto themarketsweservethroughatotalfocusoncustomerneedsandcustomersatisfaction.

TheuniqueconstructionofBusBarsconsistingoflaminarconductorlayers,thindiel TheuniqueconstructionofBusBarsconsistingoflami narconductorlayers,thindielectric ectric andavarietyofplanarorthree-dimensionalshapes,allowsforsuperioroverall performancewhencomparedtotheperformanceofwiringharnesses.Themainbenefits ofbusbarsincludethefollowing: SpaceSavings:Significantlylessspace(asmuchas50%less)isrequiredforbusbar SpaceSavings:Significantlylessspace(asmuchas50% less)isrequiredforbusbars s versuswireharnesses. EaseofAssembly:Mountingandelectricalterminalsareintegralparts EaseofAssembly:Mountingandelectricalterm inalsareintegralpartsoftheBusBar oftheBusBar andcanbelabeledusingavarietyofmethods.Thistransl andcanbelabeledusingavariety ofmethods.Thistranslatesintofasterassemblyand atesintofasterassemblyand easierrepair,whichresultinlowermanufacturingandfieldcosts. ImprovedElectricalPerformance:Alowchar ImprovedElectricalPerformance:Alowcharacteristicimpedanceisatt acteristicimpedanceisattainedduetohigh ainedduetohigh distributedcapacitanceandlowinductancethatresultfromlargersurfaceareasand rectangularcrosssectionalareas. HigherCurrentCarryingCapability:Largercrosssectionalareascanbeaccommodated. BetterThermalPerformance:Thelargersurf BetterThermalPerformance:Thelargersurfaceareacanallowforbetter aceareacanallowforbetterheatdissipation heatdissipation andbetterairflow. IncreasedLong-termReliability:Thebusbarconstructionallowsforamorecompact IncreasedLong-termReliability:Thebusbarconstructi onallowsforamorecompact design.Theproductiseasiertohandle,easiertoassembl design.Theproductiseasi ertohandle,easiertoassembleandlesspronetoelectrical eandlesspronetoelectrical ormechanicalfailures.





















ThisBusBarDesignGuidehasbeenwrittento ThisBusBarDesignGuidehasbeenwrittentoaidthosewhoareinvolvedint aidthosewhoareinvolvedinthedesign, hedesign, specification,evaluationandprocurementofbusbarsforuseinel specification,evaluation andprocurementofbusbarsforuseinelectronicsystems.The ectronicsystems.The informationcontainedhereinisprovidedasageneralguide,w informationcontainedherein isprovidedasageneralguide,withinformationcovering ithinformationcovering designandproductconsiderations,atypicaldesignexample,andsupportinformation. Thisdesignguideisnotonlyintendedinprovidingtheuserwiththenecessary information,formulasandmaterialdatato information,formulasandmaterialdatatodesignabusbar,butalsotoprovoket designabusbar,butalsotoprovoketheuser heuser intoathoughtprocessthatwillresultinat intoathoughtprocesst hatwillresultinathoroughreviewofallaspectsof horoughreviewofallaspectsofthebusbar thebusbar design.

Givenasetofelectrical,mechanicalandenvironmentalbus Givenasetofelectrical,mechanicalandenvironmentalbusbarrequirements,thefocus barrequirements,thefocus ofthedesignprocessistofindtheoptimumcombinat ofthedesignprocessisto findtheoptimumcombinationofmaterials,confi ionofmaterials,configurationsand gurationsand manufacturingprocessesthatwillyieldafinishedproduct manufacturingprocessesthatwill yieldafinishedproductthatmeetstherequirements thatmeetstherequirementsof of theapplication.

Thestartingpointforbusbardesignisidentifi Thestartingpointforbusbardesignisidentificationofthevoltage(s)andcurr cationofthevoltage(s)andcurrent(s)that ent(s)that thebusbarwillberequiredtodistribute.T thebusbarwillberequiredtodistribute.Then,acandidatecrosssectionalareacanbe hen,acandidatecrosssectionalareacanbe selectedandaninitialconductorlayoutcanbedesigned.Theelect selectedandaninitialconductor layoutcanbedesigned.Theelectricalpropertiesofthe ricalpropertiesofthe conductor(s)mustthenbeevaluatedtodetermineifthevoltageandcurrentrequirements willbemet. Themostimportantelectricalpropertyisresist Themostimportantelectricalpropertyisresistance,whichappliestoall ance,whichappliestoalltypesofvoltages typesofvoltages andcurrents.IfthebusbariscarryingACcurrent andcurrents.Ifthebusbar iscarryingACcurrentorDCswitchingc orDCswitchingcurrents,two urrents,two additionalelectricalpropertiesneedtobeconsidered:capacitanceandinductance.Each ofthesecausesitsowntypeofreactance(oppositiontoelectricalchange).Those reactancescontributetotheimpedanceofthebusbar,whichisresistance(tosteady current)plusthetotalreactance

Conductorresistanceiscalculatedfromtheresistivityoftheconductormaterialandt Conductorresistanceiscalculatedfromtheresistivity oftheconductormaterialandthe he cross-sectionalareaoftheconductor: R=ρ / A ohms/foot

(2.1)

Where, ρ=resistivityinohmsxsqmilsperfootfromTable3

A=crosssectionalareainsqmilscalculatedfrom A=crosssectionalareai nsqmilscalculatedfromformula(2.7)below formula(2.7)below Currentthroughtheconductorwillgenerateheat,andtheresistanceoftheconductorwill Currentthroughtheconductorwillgenerateheat,andtheresist anceoftheconductorwill thenincreaseproportionallytotheheat.Thissoundsli thenincreaseproportionally totheheat.Thissoundslikeanout-of-controlspiral, keanout-of-controlspiral,butthe butthe systemwilleventuallycometoanequilibriumdet systemwilleventuallycometoanequilibriumdeterminedbytheamountofheat erminedbytheamountofheat dissipatedbythesurroundingsofthebusbar.Anallowablet dissipatedbythesurroundingsofthe busbar.Anallowabletemperaturerisewillneed emperaturerisewillneedto to bedetermined,thentheresistancerecalculatedatthattemperat bedetermined,thentheresist ancerecalculatedatthattemperaturetochecktheimpact uretochecktheimpact onbusbarperformance. R2=R1[1+α (T2(T2-T T1)] 1)]

ohms ohms//foot foot (2.2 (2.2))











R1=resistanceat20°Cinohms/foot T1=20°C T2=newoperatingtemperaturein°C, α=temperaturecoeffi =temperaturecoefficientofresistivity cientofresistivityofthematerialfrom ofthematerialfromTable3 Table3

ThevoltagedropcanbecalculatedusingOhm’sLaw. ∆V=Rx ℓ x I

(2.3)

Where, ∆V=voltagedropinvoltsintheentireconductorlength R=resistanceinohms/footascalculatedfromformula(2.1)or(2.2) ℓ=conductorlengthinfeet I=currentinamperesgivenbytheamperagerequirementsoftheapplication

Ifthevoltagedropdoesnotmeettheapplicationrequirements,considerincreasingthecross Ifthevoltagedropdoesnotmeettheapplicationrequir ements,considerincreasingthecross sectionalareatolowertheconductorresistance.

Thecapacitanceisdirectlyproportionaltotheconductorareaandthedielectricconstant,and Thecapacitanceisdirectlyproportionaltotheconductorareaandt hedielectricconstant,and inverselyproportionaltotheinsulationthickness,asshown inverselyproportionalt otheinsulationthickness,asshownbythisformula: bythisformula: C=0.224(k)(w)( ℓ )/d )/dpic picofa ofards rds (2.4) (2.4) Where, k=dielectricConstantoftheinsulationused w=conductorwidth ℓ=conductorlength d=thicknessofdielectric (ℓ,wanddareininches)

Lowinductanceisacriticalelementforcontrolledandefficientoperationof Lowinductanceisacriticalelementforcontrolled andefficientoperationofthebusbarasit thebusbarasit preventsexcessivetransientovershoots.Theinductanceofatwolayerbusbarcanbe calculatedbyusingthisformula: L=31.9( ℓ )d/wnanoHenrys(2.5) Where, ℓ=lengthofconductor d=dielectricthickness w=conductorwidth (ℓ,d&wareininches)













LowcharacteristicimpedanceimprovesthebusbarperformanceforACloads,orduringthe LowcharacteristicimpedanceimprovesthebusbarperformanceforA Cloads,orduringthe transitionwhenloadcurrentsareswitching.

Ohms (2.6) Where, L=inductance C=capacitance Ass Assum umpt ptio ion: n:

Effe Effect ctiv ive elo loss ssl les ess sco cond nduc ucto tors rsa and ndd die iele lect ctri ric. c.

Therequiredcrosssectionalareaofacopperconductorforagivenamperagerequirement andatemperatureriseof30°Cmaxfromambientcan andatemperatureriseof 30°Cmaxfromambientcanbedeterminedbythefollowi bedeterminedbythefollowing ng formula: A=300x A=300xIx[ Ix[1+ 1+.075(N .075(N-1)] -1)]Sq.M Sq.Mills ills 

(2.7)

Where, I=currentinamperes N=numberofconductors Formultiplelayerbusbars,thecrosssectionalareacalculatedforeachconductorshouldbe increasedbyapproximately7½%toaccountforthedecreaseinheatdissipationbetween conductors.Thisisalreadyaccountedforinformula(2.7)above

Thewidthcalculationforagivencrosssectionalareacanbedeterminedbyselectingan Thewidthcalculationforagivencrosssectionalareacan bedeterminedbyselectingan appropriatestandardthicknessandusingthefollowingformula: 6

w=A/(1x10 )/tconductorwidthininches(2.8) Where, A=crosssectionalareaascalculatedfromformula(2.7) t=conductorthicknessininchesselectedfromthelistbelow











calculatedforthesamecurrentusingalltheavailablestandardwidths.Thecorresponding calculatedforthesamecurrentusingalltheavailablest andardwidths.Thecorresponding resistivityandinductance/lengtharecalculatedforeachthicknessandcalculatedwidth.

Inadditiontotheelectricaldesigncharacteristics Inadditiontotheelectricaldesigncharacteristicsofthebusbar,themechanicaldesi ofthebusbar,themechanicaldesign gn characteristicsshouldalsobeaddressed.Thefollowingaresomeaspectstoconsider.

Busbarshapewillbeaffectedbyterminationlocations,enclosureconstraints,operating Busbarshapewillbeaffectedbyterminationlocati ons,enclosureconstraints,operating environment,andmountedcomponents.Whendeterminingoveralldimensionsfora laminatedbusbar,allowforsufficienti laminatedbusbar,all owforsufficientinsulationextensionbeyondtheconductor.T nsulationextensionbeyondtheconductor.Theexact heexact amountofextensiondependsoninsulatingmaterialused,overall amountofextensiondependsoninsulat ingmaterialused,overallthicknessofthebusbar, thicknessofthebusbar, operatingenvironment,operatingvoltageandmethodofseali operatingenvironment,operati ngvoltageandmethodofsealing.Ultimatelyt ng.Ultimatelythefinalshape hefinalshape ofthebusbarisatradeoffbetweenapplicationrequirem ofthebusbarisatradeoffbetweenapplicationrequirements,manufacturingcapabilit ents,manufacturingcapabilityand yand cost. Basicshapes: •

Planarconductors-square,rectangle,circular,orzigzag

•

On-edgeconductors-straight,“L”,“U”,“S”,“T”,andzigzag

•

Formedconductors–flatoron-edge

Temperatureandvibrationareacouplestressestoconsiderthatcouldaffectthe performanceandreliabilityofthebusbar.Al performanceandreliabilityof thebusbar.Alsonotethatforsomeapplicat sonotethatforsomeapplications,thebusbar ions,thebusbar canactasareinforcementmemberorstiffeningcomponentfor canactasareinforcementm emberorstiffeningcomponentfortheassembledsystem. theassembledsystem.

Insomeapplications,terminationoptionsarefixed,suchasforIGBTs. Insomeapplications,terminationoptionsarefixed, suchasforIGBTs.Forothermethods, Forothermethods, considerthetypeofenvironmenttheconnectionwillneedtow considerthetypeofenvironment theconnectionwillneedtowithstand.Easeof ithstand.Easeofassembly assembly andfieldserviceaccessibilityareissuestoconsideraswell.

Themountingmethodusedcandependonanumberoffactorsthatincludetheweight,size, Themountingmethodusedcandependonanumberoffactorsthatincl udetheweight,size, easeofassembly,terminationlocations,enclosureconstraintand easeofassembly,terminat ionlocations,enclosureconstraintandaccessibilitytoother accessibilitytoother systemcomponents.Inmostcasesthebusbarissecuredusingfastenersthroughthebus barbodyorbytheterminations.Sinceholesthroughaconductorreducethelocalcross sectionalarea,thedesignermustcompensateforanyreductionincurrentcarrying











Anotherconsideration,whichissometimesoverlooked,isthetypeofenvironm Anotherconsideration,whichissometimesoverlooked,i sthetypeofenvironmentthebusbar entthebusbar andassembledsystemwillbesubjectedtoduringtransportation.Duringthedesignphase theenvironmentalsuitabilityofthefollowi theenvironmentalsuitabi lityofthefollowingshouldbeconsidered:conductormateri ngshouldbeconsidered:conductormaterial,out al,out gassing,platingmaterialandthickness,innerandouter gassing,platingmateri alandthickness,innerandouterinsulationmaterial, insulationmaterial,termination termination method,edge-sealingmethod,backfillingofbushingsandconform method,edge-sealingmethod,backf illingofbushingsandconformalcoatingifused. alcoatingifused. Choosingtherightmaterialsandconstructionmethodswill Choosingtherightmateri alsandconstructionmethodswillhelptoassurethatthebus helptoassurethatthebusbar bar performswellunderthespecifiedenvironmentalconditions.

Busbarscanbeclassifiedintotwobasiccategories, and .Asingle layerbusbarconsistsofonlyasingleconductorlayerthatisei layerbusbarconsistsofonlya singleconductorlayerthatiseitherinsulatedorun-insulated. therinsulatedorun-insulated.  Multi-layerbusbarscontaintwoormoreconductorsthatare Multi-layerbusbarscont aintwoormoreconductorsthatareseparatedbyinsulatinglayers. separatedbyinsulatinglayers. Multi-layerbusbarscanalsobeinsulatedorun-insulatedont Multi-layerbusbarscan alsobeinsulatedorun-insulatedontheoutermostconductorlayers. heoutermostconductorlayers. Asubcategoryforbothtypesofbusbarsisthatofaddedvalu Asubcategoryforbothtypes ofbusbarsisthatofaddedvalue.Basically,thebus e.Basically,thebusbarwill barwill containadditionalcomponentssuchasfuses,breakers,cableextensions,supportbrackets andotherdevicesasrequiredbytheapplication. Aftermakingadecisiontouseasinglelayerormulti-layerbusbar,onemust Aftermakingadecisiontouseasinglelayerormul ti-layerbusbar,onemustconsiderand considerand choosefromavarietyofdifferentinsulationconfigur choosefromavarietyof differentinsulationconfigurationsandsealingmethods.T ationsandsealingmethods.Thereare hereare manyconstructionoptionstochoosefromforboththeinsulat manyconstructionoptionst ochoosefromforboththeinsulationandsealingmethods,and ionandsealingmethods,and theysomewhatdependonwhetherasinglelayerormulti-layerbusbarhasbeenchosen. For

,theoptionsare: •

FlexibleDielectricFilm

•

RigidEpoxyGlassBoard

•

PowderCoating

Selectingtherightouterinsulationoptionw Selectingtherightouterinsulationoptionwilldependonsuchfactorsastheoperat illdependonsuchfactorsastheoperating ing environment,numberofconductorlayersandcost. For

onmulti-layerbusbars,theoptionsare: •

FlexibleDielectricFilm

•

RigidEpoxyGlassBoard

Selectingtherightinnerinsulationoptioncandependoncapacitanceand/orinductance requirements,voltagepotentialsandoperatingenvironment.I requirements,voltagepotent ialsandoperatingenvironment.Itisalsopossibletopow tisalsopossibletopowdercoat dercoat











Cavitation-arigidepoxyglassinsulationmaterial Cavitation-arigidepoxyglassinsulationmaterialwithmachinedpocketsfor withmachinedpocketsfor theconductorsareusedasinnerandouterinsulationlayerswhich completelyencapsulatetheinnerconductorswhenlaminated togetherwithanadhesive.Thisoptionisalsoemployedin extremeenvironments.

•

•

PowderCoating-alloutersurfacesarecompletel PowderCoating-alloutersurfacesarecompletelycoatedwithanepoxythatis ycoatedwithanepoxythatis curedtoformaprotectiveinsulation.This curedtoformaprotecti veinsulation.Thisoptioniswell optioniswell suitedforextremeenvironments.

Table1summarizestheinsulationandsealingconfigurations Table1summarizesthei nsulationandsealingconfigurationsforagivenbusbartype. foragivenbusbartype.

None

Pinch Edge Off Potting

Powder None Coating

Pinch Edge Powder Cavitation Off Potting Coating

None Flexible Film RigidEpoxy GlassBoard Powder Coating

Copperalloy110istheconductormaterialtypicallyusedinbusbardesigns.Ithasl Copperalloy110istheconductormaterialtypicallyusedi nbusbardesigns.Ithaslower ower resistivitythanbrassandaluminum,whicharealso resistivitythanbrassand aluminum,whicharealsoused.Table2andTable3l used.Table2andTable3listsome istsome relevantphysicalandelectricalpropertiesofthemostcommonlyusedconductor materialsinbusbarfabrication.











Copper 110

8.1

101

.393

Copper 101

8.1

101

.393

Brass Alloy 260

29.06

28

.098

Aluminum 6061- T651

13.35

62

.423

Avarietyofmaterialscanbeusedforinsulation Avarietyofmaterialscanbeusedforinsulationbetweenconductorsandfortheouter betweenconductorsandfortheouter covers.Ifthebusbaristobeedge-filled,ar covers.Ifthebusbar istobeedge-filled,arigidmaterialisrecommended igidmaterialisrecommendedfortopand fortopand bottominsulators.Iftheouterinsulation bottominsulators.Iftheouterinsulationissealedbypinchbonding,we issealedbypinchbonding,werecommendthe recommendthe useofaflexibledielectricfilm. useofaflexibledielectricfilm.Table4showssomerelevantspecif Table4showssomerelevantspecificationsforthe icationsforthe materialstypicallyused.ThedatapresentedinT materialstypicallyused.ThedatapresentedinTable4isforthebasemater able4isforthebasematerialwithout ialwithout adhesive.

EpoxyGlass (FR4/G-10) (1)

Mylar

(1)

Kapton

.010 - .125

4.3

1250

140

12-16

.003 .005 .010

3.3

7,500

120

17

200

17

.001 .002 .003

(3)

3.9

6000 5000 4500

94V-0

388

94VTM-2 400-600

94V-0

100-175













Tin

13.6

.42

ASTM B545, MIL-T-10727

Nickel

11.8

.48

AMS 2403,AMS-QQ-N-290, QQ-N-290

Silver

105.8

.38

ASTM B700

Solder Alloy 60/40

10.0

.40

AMS-P-81728, MIL-P-81728

Thereareavarietyofdifferentelectricalgradeepoxyresinsthatcanbeusedtoedgefil Thereareavarietyofdifferentelectricalgradeepoxyr esinsthatcanbeusedtoedgefill l busbars.Thesematerialsarespecificallychosenbythebusbar busbars.Thesematerials arespecificallychosenbythebusbarmanufacturertomeet manufacturertomeet thephysical,electricalandenvironmentalrequirementsoftheapplicationandthe limitationsimposedduringthemanufactureofthebus limitationsimposedduringthemanufactureofthebusbar.Eachmanufacturermay bar.Eachmanufacturermay standardizeonapottingcompoundthatissuitedtoitsownprocessingcapabilities, thereforenotallmanufacturersusethesamematerial.

Therearemanydifferentoptionstoterminatethebusbarforsystemconnections. Therearemanydifferentoptionstoterminatethe busbarforsystemconnections.Some Some factorstoconsiderwhenselectingaterminationtypearecurr factorstoconsiderwhenselect ingaterminationtypearecurrentrequirements,assembly entrequirements,assembly ease,andsystemvibrations.Table6describessomeofthem ease,andsystemvibrations. Table6describessomeofthemostcommonmethods. ostcommonmethods.











Considerationsformountingthebusbararebusbarweight,systemvibration,easeof Considerationsformountingthebusbararebusbarweight, systemvibration,easeof assembly,enclosurerestraintsandfieldmaintenance.Insulated assembly,enclosurerestraint sandfieldmaintenance.Insulatedthru-holesinthebusbarare thru-holesinthebusbarare mostcommonformounting.Dependingonneed,alternativemethodsincludeaseparate mountingbracketorevencabletieswitheyelets.Whenusi mountingbracketorevencablet ieswitheyelets.Whenusinginsulatedmountingholes,the nginsulatedmountingholes,the holeintheconductorneedstobelargerthanthemountinghole holeintheconductorneedstobe largerthanthemountingholediameterinorderto diameterinorderto accommodatetheinsulatingwasher,andplacedaminimum accommodatetheinsulatingw asher,andplacedaminimumof0.030”fromtheconductor of0.030”fromtheconductor edge.

Partsaretypicallymarkedwithapartnumberanddat Partsaretypicallymarkedwithapartnumberanddatecodebystampingorscreen-printi ecodebystampingorscreen-printing. ng. Partscanalsoincludecagecodeandterminationidentificati Partscanalsoincludecagecodeand terminationidentificationsperMIL-STD-130. onsperMIL-STD-130.For For stamping,thestandardcharactersizeistypically0.060”to stamping,thestandardcharactersi zeistypically0.060”to0.130”.Forscreen-print 0.130”.Forscreen-printing,the ing,the charactersizeiscustomerspecified.Anotheroptionis charactersizeiscustomerspeci fied.AnotheroptionistouseaULapprovedlabel,w touseaULapprovedlabel,which hich offerstheopportunitytousebarcodes.Avarietyof offerstheopportunityt ousebarcodes.Avarietyoflabelsizesareavailable. labelsizesareavailable.

Whendesigningabusbar,onemustnotforgettoconsiderthei Whendesigningabusbar,onemust notforgettoconsidertheissueoftestingrequirements. ssueoftestingrequirements. Thiscanincludeinitialqualificationtest Thiscanincludeinitialqualificationtestingaswellasproduction ingaswellasproductiontesting.Bothenvironmental testing.Bothenvironmental andelectricaltestingrequirementsneedtobeconsideredandspecifi andelectricaltestingr equirementsneedtobeconsideredandspecified,ifnotonthefini ed,ifnotonthefinished shed productprintatleastinaseparatedocumentthatisr productprintatleastinaseparatedocumentthatisreferredtointhefini eferredtointhefinishedproductprint. shedproductprint. Whenconsideringinitialqualificationtesting,itisagoodideato Whenconsideringinitialqualificationtesting, itisagoodideatouseMil-Std-202andMil useMil-Std-202andMil-Std-Std810asguidelinesforspecifyingtestproceduresforbusbars.Speci 810asguidelinesforspecifyi ngtestproceduresforbusbars.Specifiedtestsandcondition fiedtestsandcondition levelsshouldbecarefullychoseninordertobestqualifyt levelsshouldbecarefullychoseni nordertobestqualifythebusbarforitsintended hebusbarforitsintended application.Initialqualificationtesti application.Initialqualificationtestingcanbequiteexpensiveandcanoftentake ngcanbequiteexpensiveandcanoftentakemany many monthstoperform,dependingonthelevelanddegreeoftesting. monthstoperform,depending onthelevelanddegreeoftesting.Therefore,onemust Therefore,onemustbe be prudentindevelopingaqualificationplan,beingcarefulnottoover-specify.











Table7listsCCI’sstandardcapabilitiesandtoler Table7listsCCI’sstandardcapabilitiesandtolerances.Iftightert ances.Iftightertolerancesarerequired, olerancesarerequired, pleasecontactus.

Maximum length:

96”

Maximum width

30”

Minimum single conductor bend radius

Equals conductor thickness

Mountingholelocation

±0.020”

Mountingholediameter

±0.010”

Mountingholetoconductoredge

±0.030”

Tabtotab,singleconductor

±0.010”

Tabtotab,multipleconductors

±0.030”

Tabholediameter

±0.005”

Tabholetotabedge

±0.010”

Formedangles

±2°

Overalllength,width

±0.030”











ElectricalBusBarRequirements: :300Ampsoperatingcur :300Ampsoperatingcurrent@30°C rent@30°Cmaxtempri maxtemprise. se. MinimumVoltagedropMax.Capacitance,andMinimumInductance

.

MechanicalandPhysicalRequirements: TwoLayer,RigidEpoxyGl TwoLayer,RigidEpoxyGlassBoard,E assBoard,EdgePotting; dgePotting; Planar;Dimensions 24”longby1.5”widemax; Copperalloy110,Mylar Copperalloy110,MylarTedlarInnerIn TedlarInnerInsulation,; sulation,; ThreadedFastener; Insulatedthruholes Highhumidityenvironment

Design Parameter Cross Sectional Area Conductor Width(w)& Thickness(t)

Results A=300xIx[1+.075 A=300xIx[1+.075(N-1))( (N-1))(2.7) 2.7) I=300Amps N=2layers A=300x300x[1+. A=300x300x[1+.075(2-1))=96, 075(2-1))=96,750sqmils 750sqmilsor0.097sqi or0.097sqin n

A=0.097Sqin

w=A/t(2.8)

t=0.093” w=1.032”

t=Selectedthicknessva t=Selectedthicknessvaluesfromth luesfromtheavailableSt eavailableStdthicknesst dthicknessto o getthemaximumw/ getthemaximumw/tratioandpr tratioandpracticaltot acticaltotheapplication heapplication  A=0.097sqin Thickness (t) 0 .125” 0.093” 0.062” Width (w) 0.776” 1.043” 1.564” w / t Ratio 6.20 11.21 25.23 Thewidthrequirementis1 Thewidthrequirementis1.5”maxther .5”maxtherefore11.21(. efore11.21(.093”/1.043”) 093”/1.043”) isthemaxw/tratio isthemaxw/tratiopracticalto practicaltotheapplicat theapplication ion

Resistance

Minimum.

(Optionalmethod) UseAmpacityTableAin UseAmpacityTableAintheappendix theappendixandselectth andselectthecombination ecombination ofw&tpracticalto ofw&tpracticaltotheapplicati theapplicationandwhichw onandwhichwillyieldt illyieldthelowest helowest inductance(maxw/tratio) R=ρ / A ohms/foot (2.1) =8.1(•sqmil/ft)atAmbi •sqmil/ft)atAmbientTemp.20 entTemp.20°C,Table3 °C,Table3

t=0.093” w=1.040” R=0.08 Milli Ω/foot











CCI’sbusbardesignandmanufacturingprofessionalsstandreadytosupportyour productrequirementsandworkdirectlywithyoutofindt productrequirementsandworkdi rectlywithyoutofindtherightsolutionstom herightsolutionstomeetyour eetyour technicalandcostrequirements.Wehaveoverthirtyyearsofdesignandmanufacturing experienceprovidingpowerdistributionsolutionstoavarietyofmarkets tocontactatechnicalsupportrepresentative.

Ourcommitmenttomeetingcustomerrequirements Ourcommitmenttomeetingcustomerrequirementsandproductspecificationsisthe andproductspecificationsisthe catalystforprovidingsuperiorproductqualityatcompetit catalystforprovidingsuperior productqualityatcompetitiveprices.Wehaveestablished iveprices.Wehaveestablished businessrelationshipswithmanycompaniesasanapprovedvendorandinvarious marketsincludingmilitary,aerospace,transportation,medicalandothers. Wehaveawell-establishedanddocumentedqualitysystem,whichisISO-9001 compliant.Productqualityperformanceiswel compliant.Productqual ityperformanceiswelldocumentedfromincomingm ldocumentedfromincomingmaterials aterials inspectiontofinaloutgoinginspection.Specifi inspectiontofinaloutgoinginspection.SpecificdatarequirementssuchasFA cdatarequirementssuchasFAI(First I(First ArticleInspection)reportscanbeprovided.

Beyondproductqualityisourlong-termcommitmenttocustomersatisfaction. Beyondproductqualityisourlong-termcommitment tocustomersatisfaction.Wework Wework closelywithourcustomers,respondingpromptlytot closelywithourcustom ers,respondingpromptlytotheirneeds.Ourstaffi heirneeds.Ourstaffisdedicatedto sdedicatedto makingeverycustomerarepeatcustomer. tocontactacustomerservicerepresentative.

Wecanreceivecustomerdrawingsusing.pdffilesbutpreferthe Wecanreceivecustomerdrawingsusi ng.pdffilesbutprefertheuseofAutoCAD'snati useofAutoCAD'snative ve













Lowcomplexitybusbarswouldbeofthevarietyencompassinglowconductorlayer count,planarwithacoupleofbends,pinch-offedgeseal,nobushi count,planarwithacoupl eofbends,pinch-offedgeseal,nobushings,minimalhardware ngs,minimalhardware andsimplefastenertabs. Mediumcomplexitybusbarswouldbeofthevarietyencompassingtwotofourconductor layercount,planar,withseveralbends,pinch-offorpott layercount,planar,wi thseveralbends,pinch-offorpottededges,minimalbushings, ededges,minimalbushings, somehardware,andslightlymoresophisticatedfasteners. Highcomplexitybusbarswouldbeofthevarietyencompassingfourormoreconductor layerswithpossiblepartitionswithineachl layerswithpossiblepart itionswithineachlayercount,threedimensionalwi ayercount,threedimensionalwithcomplex thcomplex bends,pinch-offorsignificantpottededges,exoticinsulat bends,pinch-offorsignif icantpottededges,exoticinsulationmaterialswith ionmaterialswithpossible possible routinginvolved,manybushingsofdifferentsizes,muchhardwareandsophisticated fasteners.

:Theabilityofamaterialtotoleratemechanicallyinducedsurface wear.











CMA-Aunitofareaequaltothear CMA-Aunitofareaequaltotheareaofacirclewhosediam eaofacirclewhosediameteris1mil eteris1mil (0.001inch).Usedchieflyinspecifyingcross-sectionalareasof (0.001inch).Usedchieflyi nspecifyingcross-sectionalareasofconductors.Toobtainthe conductors.Toobtainthe numberofcircularmilsinaroundsolidwir numberofcircularmilsinaroundsolidwireofagivendiameter,expressthe eofagivendiameter,expressthediameterin diameterin milsthensquareit.TheCMAformul milsthensquareit.TheCMAformulaforstrandedconductoristosquare aforstrandedconductoristosquarethemildiameter themildiameter ofonestrandthenmultiplybythenumberofstrands. ofonestrandthenmulti plybythenumberofstrands.(OneCircularm (OneCircularmilisequalto ilisequalto 1/0.7854SqMilsor1.2732SqMils) Theshortestdistancethroughtheairbetweentwoconductiveelements. Thereciprocalofresistance.Theunitofconductanceisthesiemens, abbreviatedas"S."Theunitofconductancewasthe"mho,"whichwasonceshownasan upsidedowncapitalomega. :Thecapabilityofamaterialtocarryelect :Thecapabilityofamaterialtocarryelectricalcurrent,usuallyexpressedas ricalcurrent,usuallyexpressedas apercentageofcopperconductivity(copperbeing100%).Specifically, apercentageofcopperconductivity(copper being100%).Specifically,theratioofthe theratioofthe currentflowtothepotentialdifferencecausingthe currentflowtothepotentialdifferencecausingtheflow.Thereciprocal flow.Thereciprocalofresistance. ofresistance. :TheDCresistanceofapairofmatedcontacts. Theconductionofelectricityacrossthesurfaceofadielectric.











Agas-tightseal,whichpermitsmaximumgas Agas-tightseal,whichpermitsmaximumgasleakageof1.0-micronft/hr leakageof1.0-micronft/hr atoneatmospherepressure. Termforcyclespersecondbyinternationalstandard,adoptedandnowcommonin U.S.FromtheGermanphysicist'sname,H U.S.FromtheGermanphysicist'sname,HeinrichR.Hertz. einrichR.Hertz.Inusewefindthat60 Inusewefindthat60 cycles/second(or60cps)becomes60hertz(or60Hz). Thetotaloppositionofferedbyacomponentorci Thetotaloppositionofferedbyacomponentorcircuittotheflow rcuittotheflowof of alternatingorvaryingcurrentataparticularfrequency,includingboththeACandD alternatingorvaryingcurrentataparticularfrequency,i ncludingboththeACandDC C component.Impedanceisexpressedinohmsandissimilartot component.Impedanceisexpressedinohms andissimilartotheactualresistanceina heactualresistanceina directcurrentcircuit.Incomputations,impedancei directcurrentcircuit.Incomputations,impedanceishandledasacomplexratioof shandledasacomplexratioofvoltage voltage tocurrent.Theohmistheunitofim tocurrent.Theohmistheunitofimpedance.Impedanceistypicallyabbreviated pedance.Impedanceistypicallyabbreviatedas"z"or as"z"or "Z".Thefrequency-invariant,realcomponentofimpedanceisresistance.Thefrequencyvariant,imaginarycomponentofimpedanceisreactance.Thereci variant,imaginarycomponent ofimpedanceisreactance.Thereciprocalofimpedanceis procalofimpedanceis admittance. Anelectromagneticphenomenoninwhichtheexpandingandcollapsingof amagneticfieldsurroundingaconductorordevicetendstoimpedechangesincurrent. Theeffectsofinductancebecomegreaterasfrequenciesincrease.Inductanceis











Themetalliclayerappliedoverorbetweendielectri Themetalliclayerap pliedoverorbetweendielectricstopreventelectrostaticor cstopreventelectrostaticor electromagneticinterferencebetweentheenclosedconductorsandexternalfields. Thetendencyforalternatingcurrenttoflowmostlyneartheoutersurfaceof Thetendencyforalternatingcurrenttoflowm ostlyneartheoutersurfaceof asolidelectricalconductor,suchasmetalwireorr asolidelectricalconduct or,suchasmetalwireorrectangularbus,atfrequenciesabove ectangularbus,atfrequenciesabove theaudiorange.Theeffectbecomesmoreandmoreapparentasthefrequency increases.Atmediumtohighfrequenciestheskineffect increases.Atmediumt ohighfrequenciestheskineffectessentiallyreducestheeffect essentiallyreducestheeffective ive cross crosssec sectio tional nalar area eaof ofthe theco condu nducto ctora rand ndinc increa reases sesth ther eresi esista stance nce. . Theareaofasquare,whichmeasuresonemil(0.001”)byonemil(0.001”). 2 -6 Thusonesquaremilisequalto0.000001in ,or1x10 in (OneSquareMilisequalto 0.7854Circularmils). Theimaginarypartofadmittance Theratioofthechangeinresistivitytotheoriginal resistivityvalue,foraunitchangeintemperature. Thedifferencebetweentheinitialandfinal Thedifferencebetweenthe initialandfinaltemperatureofthedevice. temperatureofthedevice. Theincreaseinsurfacetemperatureofacomponentinairduetothepowerdissipationin Theincreaseinsurfacetemperatureofacomponentinairduet othepowerdissipationin











TABLE A

AmpacityTable Thistableappliestoatwo-layerbusbarusinga0.005dielectric.Itgivesthe Thistableappliestoatwo-layerbusbarusinga0.005diel ectric.Itgivesthecorrespondingcross correspondingcross sectionaldimensions,theresistivityandtheinductance/inchfor sectionaldimensions,theresi stivityandtheinductance/inchforvariousamperagerequirementsata30° variousamperagerequirementsata30°C C maxtemperaturerise.

50 50 50 50

0.016 0.016 0.016 0 016

0.020 0.040 0.062 0 093

0.806 0.403 0.260 0 173

0.042 0.042 0.042 0 042

0.198 0.396 0.613 0 920













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