HP-722A-Manual 电路图.pdf

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1、HP Archive This vintage Hewlett Packard document was preserved and distributed by Pleasevisituson the web! Scanned by on-line curator: Tony Gerbic * For FREE Distribution Only * RadioFans.CN 收音机爱 好者资料库 HEWLETT-PACKARDCOMPAY RadioFans.CN 收音机爱 好者资料库 011551 OPERATINGANDSERVICEMANUAL MODEL722A/AR SERIAL

2、SPREFIXED:105- DCPOWERSUPPLY CopyrightHEWLETT.PACKARDCOMPANY1961 1501PAGEMillROAD.PALOALTO,CALIFORNIA,U.S.A. Prioted:NOY1961 RadioFans.CN 收音机爱 好者资料库 Model 722A TABLEOFCONTENTS Tableof Contents ListofIllustrationsandTables Section ,Page VMAINTENANCE5-1 5-1.Introduction5-1 5-3.MaintenanceProcedures5-1

3、 5-4.DustcoverRemoval.5-1 5-6.Zero-SettingtheMeter5-1 5-8.PrintedCircuitBoardRemoval5-1 5-10.TestEquipmentRequired5-1 5-12.PerformanceCheck5-1 5-14.Troubleshooting.5-1 5-15.Introduction5-1 5-17.TroubleAnalysis5-1 5-20.DetailedTestProcedure5-5 5-23.ReferenceVoltageAdjustment5-6 5-25.Monitoring5-6 5-2

4、7.Voltage Range5-6 5-29.CurrentLimit5-6 5-32.PerformanceTest5-6 5-34.Voltage Range5-6 5-36.CurrentLimiting.5-7 5-38.OperationCharacteristics5-7 5-39.RippleCharacteristics5-7 5-40.LoadRegulation5-7 5-41.LineRegulation5-8 SectionPage IGENERAL INFORMATION.1-1 1-1.Introduction. . .1-1 1-4.Description. .

5、 .1-1 1-8.DifferencesinEquipment. .1-1 1-10.EquipmentSupplied . . .1-1 1-12.OtherModes ofOperation.1-1 IIPREPARATION FORUSE2-1 2-1.Unpacking andMechanicalInspection2-1 2-4.SiteSelectionandInstallation2-1 2-6.LinePower2-1 2-8.Operationfrom230-Volt Supply2-1 2-11.PreparationforStorageand Shipment2-1 2

6、-14.Storage2-1 2-16.IncomingInspection 0to2amperesdc LINE REGULATION:Lessthan 2.5mvchangefor10%linevoltagechange; outputset between 0to60volts LOAD REGULATION:Lessthan 5mvchangeatoutputterminalsfor0to2ampereschange; outputsetbetween 0 and 60volts TRANSIENT RECOVERY TIME:Lessthan 20011secforrecoveryw

7、ithin 5mvforachangefrom0to fullloadorfullloadto0atanyratedoutputorlinevoltage NOISEANDRIPPLE:Lessthan 25011vrms TEMPERATURESTABILITY:Betterthan0.02%jOCor5mvJOC,whicheverislarger TEMPERATURERANGE:oto550foroperationwithinspecifications OUTPUT IMPEDANCE:DC:Lessthan 2.5milliohms AC:Lessthan 5milliohmsin

8、serieswith 10Ilh OUTPUT METERS:Voltage: 0to60volts,onerange Current:0to2.5 amp, onerange PROTECTION:Outputcurrentlimitercontinuouslyadjustablefrom100 rnato2.2 a COOLING:Forcedair Iii I it 16 :E -.t a f I ,!IJ SIDE 4ii 5 t t I 19 . 722AR RackMount:DIMENSIONS: WEIGHT:RackMount: Net 34lb POWER:115or230

9、volts10%,50to60cps,40to250wattsdependingon lineandloadconditions 1-001155-1 Model 722A SECTIONI GENERALINFORMATION Section I Paragraphs1-1to1-13 1-1.INTRODUCTION. 1-2.Thisisanoperatingandservicemanualforthe Model 722ADCPowerSupply.Thismanualisappli- cableonlytoinstrumentswiththeprefixshown on thefro

10、ntcoverexceptasmodifiedbychangesheets. 1-3.Hewlett-Packardinstrumentsuseatwo-section eight-digitserialnumber,thatis,000-00000.The firstthreedigitsareanidentificationnumber;the lastfivedigitsaretheinstrumentserialnumber.If theidentificationnumberontheinstrumentdoesnot agreewiththeidentificationnumber

11、shown onthe manualtitlepage,therearedifferencesbetweenthe manualandinstrument.Thesedifferencesarede- scribedinmanualchangesheetshavingtheproper identificationnumber. 1-4.DESCRIPTION. 1-5.TheCtJModel 722ADCPowerSupplyisacom- pletelytransistorized,regulatedpowersupply.It willsupplyupto60voltsat2ampere

12、swith continuous adjustmentofvoltageandcurrentlimiting.Thecur- rentlimitcnbesetatanycurrentbetween 100ma and2amperestoprotectcircuitelements,suchas transistors,undertest. 1-6.Twometersmeasurebothcurrentandvoltage drawnbytheloadcontinuouslysothatyoumaymonitor powersupplydrainconveniently.Theoutputimp

13、edance islowforboth dc andacsothataminimumofde- couplingisrequiredincascadedcircuits.Terminals forremotesensingareprovidedontherearofthe chassissothattheohmicresistanceofthesupply leadsisminimized. 1-7.TheusefulnessoftheModel 722Aisnotlimited totransistorapplications,butisusefulwherever highstabilit

14、yisrequired.Forinstance,Model 722A isanexcellentsourceforregulatingthefilament voltageofvacuumtubes. 1-8.DIFFERENCESINEQUIPMENT. 1-9.Thismanualhasbeenwrittenandillustratedfor theModel 722AR(rack-mountedinstrument)sincethis istheonlystyleofinstrumentavailableatthetime ofwriting.Acabinet-mountmodelmay

15、becomeavail- ableinthefuture.Thismanualwillalsoapplytothe electricaldetailsofthecabinet-mountedmodeleven thoughthephysicalconfigurationmaybedifferent. 1-10.EQUIPMENTSUPPLIED. 1-11.Theequipmentsuppliedconsistsof onlythe Model 722ADCPowerSupplyasthissupplyiscom- pleteinitself. 1-12.OTHERMODESOFOPERATI

16、ON. 1-13.TwoModel 722Asmaybeconnectedinseries forgreatervoltage.Do notconnectmorethan two 722Asinseries.RefertosectionIIIforinstructions beforeattemptingtooperatethesesuppliesinparallel. 01155-1 Figure1-1.Model 722ARDCPowerSupply 1-1/1-2 Model 722A SECTIONII PREPARATIONFORUSE SectionII Paragraphs2-1

17、to2-17 ,i 2-1.UNPACKING-OREMOTE SENSING REMOTEU. 4-1 SectionIV Paragraphs4-5to4-17 4-5.Alternatingcurrentfromtheautotransformer isrectifiedinabridgerectifierCRI-4.Theoutput ofthebridgeisafull-waverectifiedacvoltage.This voltageisfilteredby thelargecapacitorC1.Thus thevoltagesuppliedto theseriesregul

18、atorisalmost puredirectcurrent. 4-6.SERIESREGULATOR. 4-7.Theseriesregulatorconsistsof twotransistors inseries,one of whichisdrivenbytheseriesregu- latordriverQ3.Theothertransistorisdrivenby Q11,thethirdstageintheamplifier.Theactionof thesecircuitsisexplainedinparagraphsunderthese titles. 4-8.OUTPUTC

19、IRCUIT. 4-9.ResistorR18isconnectedbetweentheoutput of theseriesregulatorandthenegativeoutputterminal. AnammeterconnectedacrossR18iscalibratedto readthecurrenttotheload.VoltmeterM2iscon- nectedacrossthe output andreadstheoutputvoltage. Theoutputisavailableonthefrontpanelterminals and onthereartermina

20、lstripforremoteapplication. 4-10.VOLTAGEREGULATINGCIRCUIT. 4-11.Thevoltageregulatingcircuitconsistsofthe FINE VOLTAGEadjustmentR24(refertofigure4-1), theCOARSE VOLTAGEadjustmentR25,theamplifier circuit(QI3, Q12 and Q11 andassociatedcircuitry) andtheseriesregulatorQ2.Thediodelimiters, CR20 and CR21,l

21、imittheinput totheamplifierinboth thepositiveandnegativedirections.Considerwhat happenswhentheoutputvoltagedrops.Thisdropmay bea slowshiftin outputvoltageoranacsignalonthe output.ACsignalsarefed totheamplifierthrough C5 and R40.Thislow-impedancepathincreasesthe loopgainforacsignals.When thevoltageon

22、 thebase of Q13(seefigure4-3)becomesmorepositive(less negativeaswhentheoutput ofthesupplydrops)Q13 drawsmorebasecurrentsincetheemitter-basebias isincreased(Q13isanpn-typetransistor).This signalisamplifiedandreversedinphase.When coupledtoQ12,thisreversedsignalagaincauses morecurrentto flowsincethefor

23、wardbiasisagain increased(Q12isapnp-typetransistor). 4-12.Diodes CR18 and CR19arezenerdiodeswhich providedirectcouplingbetweenthestagesinthe amplifierandmaintainpropercollectorvoltageson thetransistorelements.Thesediodesarekeptinthe zenerbreakdowncondition bythecurrentsflowingin resistorsR35,R36,R38

24、,and R39.Thesignalis amplifiedandinvertedinQ12.CapacitorCIS,in- ductanceLlandresistorR31intheemittercircuit of Q12helpstabilizetheloop.Theemitterof Q12 isconnectedthroughthesecomponentsto a point which isseparatedfromthepositiveoutputterminalbyre- sistorR33.Loadcurrentthroughthisresistorinjects curr

25、entfeedbackintotheloop whichimprovestheload regulation.TheinvertedsignalfromQ12tendsto 4-2 Model 722A reducethebasecurrentinQ11(apnp-typetransistor). Thesignalisamplifiedandinvertedin Q11and fed to thebaseof Q2.Thissignaltendstoincreasethe currentthroughQ2(anotherpnp-typetransistor). Increasingthecu

26、rrentthroughQ2increasesthevolt- ageout ofthesupply.Sincetheoriginalactionwas adecreaseinvoltagethisactionwill tend torestore theoriginalconditions,regulatingthesupply. 4-13.Thedcoutputvoltageissetbyvaryingthe COARSE and FINE VOLTAGEcontrolsR24 and R25. Inexplainingthiscircuit,resistorR51canbethought

27、 ofasaconstant-currentsource.Mostofthiscur- rentnormallyflows outthroughR24 and R25tothe seriesregulatorwith only aninsignificantamount going tothebaseof Q13.Thusastheresistanceof R24 and R25isincreasedthevoltageonthenegative outputleadwill gofurthernegativesincetheconstant currentthroughtheseresist

28、orswill develop agreater voltagedrop. 4-14.CURRENT-POWERLIMITER. 4-15.TransistorQ4plusassociatedcircuitryforms aprotectivecircuitwhichlimitsthecurrentandpower dissipationintheseriesregulatorsandload.Refer- ringtofigure4-3,nocurrentflows throughQ4under normalconditionssincethebaseisbiasedpositive wit

29、hrespecttotheemitter.Themaximumcurrent availableforthebaseofQ2isfixed bytheresistors RIOandRllandthereferencesupply.Normally,the currentnotusedbythebaseofQ2to supply acertain loadcurrentpassesthroughthecollectorofQl1. 4-16.Whentheinstrumentisinthecurrent-limiting condition,itisessentiallyaconstant-c

30、urrentsupply ratherthan avoltagesupply.Thevoltagederived acrossR18iscoupledtothebaseofQ4throughCR8 and R14.As theloadcurrentincreases,thisvoltage increasestoalevelwhereQ4beginstoconduct.Any attempttoincreasetheloadcurrentfurthermerely turnsQ4onharder,deprivingQ2ofthenecessary basecurrenttosustainthi

31、slargerloadcurrent.This actiontendstokeeptheloadcurrentconstant.Since theoutputvoltageisbelowthedesiredoutputvoltage inthecurrent-limitingcondition,theamplifierturns offQl1.WithQ11turnedofftheonlypathsforthe currentthroughRIO and R11areintothebaseofQ2 andthecollectorof Q4. 4-17.Referringtofigure4-3,

32、astheloadresistance isfurtherdecreasedtheoutputvoltagedecreases sincethecurrentisheldconstant.Thistendstoin- creasethevoltageacrosstheseriesregulator.When thisvoltagereachesacertainvalue,thezenerdiode CR6 willstartto conduct.Thiscurrentappearsto Q4tobeduetoincreasingloadcurrentandQ4tends toconductmo

33、recurrentawayfromthebaseofQ2thus decreasingtheloadcurrentandlimitingthemaximum dissipationintheserieselements.Diode CR8acts asa 0.7 voltbatterysinceitisforwardbiasedatall timesbythecurrentthroughR12.ResistorR14ad- juststhelowerlimitofthecurrentlimitrangewhile R20adjuststheupperlimit.TheCURRENT LIMIT

34、 potentiometerR5adjuststhecurrentlimittoanyvalue betweentheupperandlowercurrentlimits. 01155-1 Model 722ASectionIV Paragraphs4-18to4-20 ! Vc FROMRI8 -+ RECTIFIERS Q2 RSAR7 + RI2 CI LOAD R33FROM +-+-.-.JI,/Ify-. RECTIFIERS CISLIR37RSI 50-11-868 + Figure4-3.CurrentPowerLimiter 4-18.PROTECTIONCIRCUITS.

35、 4-19.Referringtotheschematicinthebackofthe manual,notethatrelayKlisshowninthenormal energizedposition.Whentheinstrumentisturned off,orifthepowerfails,therelaywillreturntothe oppositepositionimmediately.Thecentercontacts oftherelayKlontheschematicthen apply a fixed positivebiastothebaseofQ2tendingto

36、turnitoff. Ifthiswerenot donetheoutputvoltagewouldhavea transientimpresseduponitduetothefactthatthe amplifierlosescontroloftheserieselementsfaster thanthelargeinputcapacitorC1canbedischarged throughR3.NotethattherelayswitchesR3across Clwhen apowerfailureoccurstohelpdischargeCl. 4-20.Whentheinstrumen

37、tisfirstturnedontherelay Klisintheoppositepositiontothatshowninthe schematicattheend ofthismanual.Thevoltageapplied 01155-1 tothecoilofKlmustfirstchargecapaCitorsC13 and C14throughR31beforetherelaycoilbecomes energized.Whenthesecapacitorschargeup,the relaycoilwillbecomeenergizedandtherelay contactsw

38、illswitch,providingatime-delayinturn-on. ThetopsetofcontactsswitchR2 out ofthecircuit. Thisresistanceisusedduringtheinitialtime-delay periodtolimitthein-rushofcurrentthroughthe bridgerectifiersCRI-4.Themiddlesetofcontacts switchthebaseofQ2froma fixedpositivevoltageto itsnormaloperatingcondition.This

39、positi-vevoltage keepsQ2turnedoffduringtheinitialturn-ondelay, givingtheamplifiertimesoitsvoltagescanreach theiroperatinglevelsandgaincontrolofthefeedback loop.Thisactionwillpreventoutputvoltagetransients whichcouldexceedthedesiredoutputvoltage.The bottomsetofcontactsdischargethecapacitorsC13 and C1

40、4throughR32,preparingthecircuitforthe nextturn-oncycle. 4-3 Section V Table5-1 Table5-1.RecommendedTestEquipment Model722A InstrumentTypeRequiredCharacteristicsUseInstrumentRecommended DCVoltmeterAccuracyof1%Measurevoltages Analog,rfiJModel412A/AR Digital,1j;Model405A/B/C ACVoltmeterAccuracyof3%Meas

41、urerippleModel403A Floatinginput Batteryoperated Oscilloscope5mv-cmsensitivityMeasureripplepeaksModel 130B, 150A with Model 151B Model 160B/170Awith Model 162D VariableMonitormeter1voltres-ChangeacinputvoltageSuperiortype UC1M Transformerolutionand1%accuracy Low-Heat23-1/2wattelementSolderprintedcir

42、cuitboards SolderingIron(connectironto75 volt line)UngarModel 776 SolderingIronHandle UngarModel 535 HeaterElement UngarModelPL333 SolderingIronTip Stable VoltageoiseandripplelessthanReferencevoltagetotestAnotherModel 722A; Source250microvoltat60voltsregulation45voltand 7voltbattery connectedinserie

43、s Load25ohmsat150wattsLoadformeasuringripple,Anyresistororcombination regulation,etc.ofresistorsofsuitablevalue (mayusewirewoundresistors, supply notaffectedbyin- ductive load) Precision1ohm1%,5 wattresistorMeasurecurrentwithstocknumber0811-0040 Resistorvoltmeter 5-0 01155-1 Model 722A SECTION V MAI

44、NTENANCE Section V Paragraphs5-1to5-18 5-1.INTRODUCTION. 5-2.Thissectioncontainsmaintenanceandservice informationfortheModel 722ADCPowerSupply. Aperformancecheckisincludedattheend ofthis sectiontobeusedtoverifyinstrumentoperation.This checkcanbemadewiththeinstrumentinitscabinet andisa goodtestaspart

45、ofpreventivemaintenance andincomingqualitycontrolinspection. 5-3.MAINTENANCEPROCEDURES. 5-4.DUSTCOVER REMOVAL. 5-5.Removetheeightscrews(fouron topandfour below) holdingthedustcoverontheinstrument.Pull thedustcoverfromtheinstrument. 5-6.ZERO-SETTINGTHEMETER. 5-7.Themeterpointermustrestonthezerocali-

46、brationmarkonthemeterscalewhentheinstrument isatnormaloperatingtemperature,restinginits normaloperatingposition,andtheinstrumentis turnedoff.Tozero-setthemeterproceedasfollows: a.Turnoninstrumentandallowittocomeupto normaloperatingtemperature(about 20minutes). b.Turntheinstrumentoff.Wait twominutesf

47、or power-supplycapacitorstodischargecompletely. c.Rotateadjustmentscrewonfrontofmeterclock- wiseuntilthemeterpointeristotheleftofzeroand furtherclockwiserotationwillmovethepointerup- scaletowardszero. d.Turntheadjustmentscrewclockwiseuntilthe pointerisexactlyoverthezeromarkonthescale. Ifthescrewistu

48、rnedtoofar,repeatstepsc and d. e.Turnmeteradjustmentscrewcounterclockwise about15degreestobreakcontactbetweenadjustment screwandpointermounting yoke, but notfarenough tomovethepointerbackdownscale.Ifscrewis turnedtoofar,asshown bytheneedlemoving,repeat theprocedure.Themeterisnowzero-setforbest accur

49、acyandmechanicalstability. 5-8.PRINTED CIRCUIT BOARD REMOVAL. CAUTION Besuretoturnofftheinstrumentand allow timeforthecapacitorstodischargebefore changingtheprintedcircuitboards.Donot attempttooperatethisinstrumentwith any oftheprintedcircuitboardmissing. 5-9.Theprintedcircuitboardsareheldinby being pluggedintosockets.Sincethesesocketshavemany 01155-1 contactstheboardisheldinquitefirmlywithout being fastenedinanyotherway.Toremovetheseboards someadditionalhelpmaybeneeded.Placeascrew- driver(right-anglescrewdriverwithboardsA:;:;:;:;:;:;:;:;