Specifications

Section-4 Theory
November 11, 2013
4‐24
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4.6.3.1 ACDistributionBoard
TheACdistributionboardconsistsofthreeidenticalgroupsofAClinefiltering,twostagesoftransientprotections
perfiltersection.FirststageoftheprotectionisformedbyanetworkofMOVswhichconnectstotheAClinefilter
inputs.Thesecondstageofprotectionprovidesahardvoltagelimits
byusinghighenergyTVSdevices,which are
connectedattheoutputofeachfiltersection.Themaximumpeakvoltageislimitedto582Vpeak,andisbelowpeak
allowedvoltagetoAC/DCconverterinterfaceboard.
Onboard48V/12VDC/DCconvertercanprovideupto1.25Aofcontinuouscurrent.
FourwireWYEwithneutralpowersystem:
FourwireWYEconfigurationsupports380/400/415Vaclinetolinevoltages.Convertersareconnectedbetweenline
andneutral,whichyields220/230/240VacL‐N.Therefore,minimumLine‐Nvoltageis187Vrms.
ThreewireDelta/WYElinetolinepowersystem:
MaxivaULXpoweramplifiermoduleemploysatotalof8powersupplyconverters.Thispresentsanunbalancedload
tothethreephasepowerlinegrid.
4.6.3.2 AC/DCConverterInterfaceBoard
AC/DCConverterInterfaceboardisa500WoutputACtoDCswitchingpowersupply.ItacceptsuniversalACinput
voltagefrom85to265Vacandtheoutputvoltageisadjustablefrom44Vto50Vdc.See
4.6.3.3onpage4‐24for
additionalinformationonhowPSvoltagesareset.
Converterisequippedwithapowerfactorcorrectionfrontendtoreducepowerlineharmonics.Becauseofthe
largeDCreservoircapacitorsconnectedtoitsDCbus,a stepstartresistorisaddedtolimittheinrushcurrentto7A
peakperconverter,thisisequalto~1.5xconverter’smaximumcontinuous
operatingcurrent.
TheAC/DCConverterInterfacePWBisapproximately2.45”x5.00”.Allmountingholesareelectricallyconnectedto
ground.Itisa4layersboard.TheAC/DCconverterboardsarefieldreplaceable.AC/DCconverter(powersupply)
replacementinstructionscanbefoundinsection
5.7onpage5‐9.
4.6.3.3 PAPS(AC/DC)VoltageSelectPath
EachPAandIPAhaseightAC/DCconverters(powersupplies)whichsupplyvoltagetothedrainseachpower
amplifierFET.DependingontheRFfrequencyofoperation,thepowersuppliescanbesetfor44Vdc,46Vdc,48Vdc
or50Vdc.Thepowersupplyoutputvoltageselectpath,from
theMCMboardintheTCUtoeachpowersupplyin
eachPAandIPAmoduleisshownin
Figure4‐14onpage4‐25.ThePAvoltageselectpathfromtheMCMboardinthe
TCUtotheIPAandPAbackplanes,showbytheboldlinesinFigure4‐14,iscarriedonpin7ofthe25conductor
CabinetBus.ThisrepresentstheonlyuseofthecabinetbusintheMaxivatransmitter.
Table4‐13PSConnectorPinAssignments
Pin Signal Description
1 AC1 Input,3.4A,240VACfusedat5A
2 NC Notconnected
3 AC2 Input,3.4A,240VACfusedat5A
4 NC
5 NC
6 GND Ground
7 GND Ground
8 DCTrim Input,6.49Kohms,0.75VDCto6.0VDC
9 DCSource Output,0.4A,50VDC
10 DCSample Output,9.09Ohm,50VDC