Kenwood PR-657 User manual

DCPOWERSUPPLY
INSTRUCTIONMANUAL
PR-657

1. GENERAL
YourPR-657isanallsolidstatevoltage-regulatedDC
powersupply,supplying0 to30V.7 A power.It
providesimprovedtemperaturecharacteristics,lineand
loadregulationsandothercharacteristics.Italsoisso
dependablethata built-inprotectivecircuitcanprotect
itagainstshortcircuitsandoverloads,thusrequiringfew
troubleshooting.Usinga remotecontrolswitchbox
.(option)allowsyoutofreelyselectanyoffouroutput
voltagesfroma distantplace.
2BFEATURES
CONTENTS
1. GENERAL2
2. FEATURES2
3.SPECIFICATIONS3
4. CIRCUITDESCRIPTION4
5.CONTROLSANDWHATTHEYDO......6
5.HOWTOOPERATE.8
7.CAUTIONSFORUSE11
8.PARTSLIST12
9.P.C.BOARD......................18
10. SCHEMATICDIAGR' ' ..............19
a. YourPR-657providesadvancedperformanceand
highreliabilityasitsdifferentialamplifierismadeup
ofSC.
b.TheICdifferentialamplifierprovideshighopenloop
gainandgoodlineandloadregulationsandlittle
ripple.
c.Theoutputvoltageiscontinuouslyvariableandcan
besetatanyof0 to30V.
d. Theoutputcurrentavailableisashighas7 A.
e.A built-inprotectivecircuitagainstoutputshortor
overloadpreventsthetransistorsfromdamage, mini-
mizingoccurrenceoftrouble.
f.Anovercurrentindicatoronthefrontpanellights
whena built-inovercurrentprotectivecircuitisin
action.
Thisishelpfulforyoursafetyoperation.
9- Presetswitchesenableyoutoinstantaneouslysetany
ofthreedefferentoutputvoltageswithoutturning
theoutputvoltagecontrol,
h.A remotecontrolswitchbox(option)allowsfreely
switchinganyoffouroutputvoltagesfroma distant
place.
2

3. SPECIFICATIONS
3
PowerSupply
Voltageregulatingcharacteristics,
Outputvoltage:0 to30V.
Outputcurrent:0 to7A.
Lineregulation(with
240V± 10%change!:Betterthan± 5mV.
Loadregulation:Betterthan10mV.
Rippteandnoise:Lessthan5mVp-p.
Residualvoltage:Within0 to+50mV.
Meters,
Voltmeter:0 to32V(fullscale).
Ammeter:0 to7.5A(fullscale).
Voltmeteraccuracy:Betterthan±3%offullscale.
Ammeteraccuracy:Betterthan±3%offullscale.
Transientresponsetime:Shorterthan450psec(with
loadturnedon).
Temperaturecharacteristics,
Temperaturecoefficient:Lowerthan200ppm/°C(0to
40°C).
Operatingtemperature:0 to50°C.
General
Line,
Inputvoltage:100,120,220,or240VAC
±10%.
Frequencyandpower
consumption:50to60Hz,below430W.
Insulationresistance:Over50betweenlineand
cabinet(with500VDC).
Outputconnectors,
Polarity:Positive(+),negative(—)and
common(COM).
Anyconnectormaybe
grounded.
Dimensions:200(208)Hx208Wx363(401)
Dmm
Valuesin( ) include
protrusion
Netweight:13.6kg.
Accessories,
Powercable:1 piece
Plugforremotecontrol:1 piece.
Replacementfuse:3A,5A,2 piecesrespectively
Instructionmanual:1 copy.

4. CIRCUIT DESCRIPTION
InstudyingtheoperationofeachcircuitinyourPR-657,
pleaserefertoFigure1,the"BlockDiagram",andthe
SchematicDiagramonthebackcover.
LINE
VOLTAGE
SELECTOR
ACLINE
AUX POWER
SOURCE
CURRENTAMP
DIFFERENTIAL
AMP
OVERCURRENT
DET
MAIN POWER
SOURCE
LIGHT
Figure1 BlockDiagram
4

MainPowerSource
TheinputACvoltageisfullwave-rectifiedbyD1(KBPC-
2502bridge),issmoothedbyC1(15,000MF),andisfed
totheCurrentAmplifier.
AuxiliaryPowerSource
Thispowersourcefeeds±15Vregulatedvoltagestothe
voltagecontrolcircuitandprotectivecircuit.Theinput
voltageisfull-waverectifiedbyD101throughD104and
isregulatedto±15V byOt01,D105,Q102andD106.
The+15V voltagealsoisusedtocreatea highly-stable,
accurate6.2V referencevoltagethroughD107a high-
temperaturecompensationzenerdiodeD108.The vol-
tageobtainedatD107isusedasthereferencevoltagefor
theovercurrentprotectivecircuit.
DifferentialAmplifier
Thisamplifiercontrolstheoutputvoltage,beingcom-
prisedof IC101, Q103,Q104andQ105.Theoutput
voltagecanbevariedwithVR1.Theadjustedvoltageis
amplifiedby IC101, ispassedthroughQ103,andis
voltageandcurrent-magnifiedbyDarlingtonamplifierof
Q104andQ105.Themagnifiedvoltageisfedthrough
theemitterfollowertothesucceedingCurrentAmplifier
stage.TheDifferentialAmplifierisstableandquickin
respondingtoa loadchangeandthelikesothatIC101
isofopenloopamplifier.
OvercurrentDetector
Thisdetectorisa protectivecircuitthatpreventsan
overcurrent,beingcomprisedofQ106,IC102andQ107.
Thevoltageinducedacrosstheoutputcurrentdetecting
resistorR12iscomparedwiththereferencevoltage
givenatD107inthecomparatorcircuitIC102.Ifthe
outputcurrentreachesitsovercurrentlimit,IC102
operates,theoutputofwhichpromptsQ106toturnon
tosuppressthebasepotentialofQ104.Thisprevents
theoutputcurrentfromincreasingmorethanlimited.
TheOvercurrentDetectorI hasa droopingconstant-
currentcharacteristic.Whentheprotectivecircuitisin
action, Q107turnsonthelight-emittingdiodeD3,
whichindicatessuchanaction.
CurrentAmplifier
ThiscurrentamplifierconsistsofQ1throughQ7,01
beinganemitterfollower.TheremainingQ2through
Q7areconnectedinparallel.
Light
Thislightisanovercurrentindicatorlight-emittingdiode
(LED).
5

5.CONTROLSANDWHATTHEYDO
6

FrontPanel
REF.
NO.
PANEL
INDICATION FUNCTION
1 A DCammeter,7Aandhigherzoneofwhicharecoloredred.
2 V DCvoltmeter.
3 OVERCURR LEDOvercurrentindicator,whichlightswhenoutputcurrentexceeds
overcurrentlimit.
4 LEDpower-onindicator,whichlightswhenPOWERON-OFFswitch
isturnedon.
5 POWERON/OFF Poweron-offswitch,whichturnsonPR-657atONposition.
6 OUTPUTON/OFF Outputon-offswitch,whichturnsonoutputvoltageisfedto
load.
7 VOLTAGE Outputvoltagecontrol,whichraisesvoltageupwhenturnedclockwise.
8 OUTPUTSELECTOR
i-n-ni
Presetvoltageswitchwhichswitchesoutputvoltagetoanyofthreevalues.
9 OUTPUTSELECTOR
PRESET/VARIABLE
Preset-variablevoltageselectorwhichatsupperpositionallowsswitch8 toselect
presetvoltageandatlowerpositionallowsVOLTAGEcontrol7 tovaryoutput
voltage.
to Negativeconnectortowhichnegativeloadisconnected.
11 Groundingconnectorearthedtochassis.Inuse,besuretoconnectthistopositive.
(+), negative(-)orCOMconnectorwithshortbar.
12 © Positiveconnectortowhichpositiveleadofloadisconnected.
7

RearPanel
13. PANEL/REMOTE Panel/remotecontrolselector,whichwassetatPANELpositionatfactory.For
remotevoltageselection;removestoppertoswitchselectortoREMOTEposition.
14 REMOTEINPUT Remotecontrolconnector.Forremotevoltageselection,connectremotecontrol
switchboxtothis 7-pin connector.
15 Linevoltageselectorofplugtype.Plugcanberemovedbypullingbackward.
Wheninserting,plugarrowmarkmustdirectratedlinevoltage.
16 Fuseholdercontaining3 A fuse.Capwillberemovedbyturningcounterclockwise
withPhillipsscrewdriver.
17 Powercableconnector.
6.HOWTOOPERATE
(DUsingVOLTAGEControl
ForoperationwiththeVOLTAGEcontrol7 onthe
frontpanel,setupthecontrolsasillustratedinFigure2.
1. SetthePRESET/VARIABLEselector9 to "VARI-
ABLE".
2. SetthePOWERON-OFFswitch5 to"ON".The
power-onindicator4 willlighttoshowthatyour
PR-657isreadyforoperation.
3.AdjusttheVOLTAGEcontrol7 clockwisefora
desiredoutputvoltage.
4. Firmlyconnecta loadtotheoutputconnectors10
and12,whicharefloatedfromthechassis.Placethe
shortbarbetweeneitheroftheseconnectorsandthe
groundingconnector.Ifnot,hummaybeinduced
intheoutputline.
5.TurntheOUTPUTON-OFFswitch6 to"ON",by
whichtheoutpriltagewillbesuppliedtothe load.
Fig. 2
8

20V
OutputCurrent 7.2A
NOTE: Iftheoutputcurrent-exceedsaround7.2A,the
overcurrentprotectivecircuitoperatesand
turnstheovercurrentindicator4 on.Thecircuit
hasa droopingconstant-currentcharacteristic
asillustratedinFigure3.
(2)AdjustingPresetVoltages
Toadjustthepresetvoltages,setupthecontrolsonthe
frontpane!asillustratedinFigure4.
1. SetthePRESET/VARIABLEselector9 to"PRE-
SET".
2. SetthePRESETswitch8 to "I".
3.AdjustthePRESETI semi-fixedcontrolontheright-
handsideclockwisewitha standardscrewdriveruntil
theV meter2 readsa desiredvoltage.
4. Similarly,proceedwithadjustmentforthePRESET
IIandIIIvoltages.
.5.Thiscompletesthepresetvoltageadjustment.Turning
thePRESETswitch8 to"l"r"JT-and"ID"-will
producethepresetvoltagesinsequence.
NOTE: Thepresetpositionoutofuseshouldbesetfor
0V outputvoltageforsafetyoperaiton.
STANDARDSCREWDRIVER
P -«e 4
7.28A
Figure3
Output
Voltage
9

(3)UsingRemoteControlSwitchBox(option)
Toremote-controlyourPR-657,setupitandtheremote
controlswitchbox;.
IMPORTANT
TurnthePOWERON-OFFswitchto"OFF"before
startingset-upprocedures.
1. Connecttheremotecontrolswitchboxcabletothe
REMOTEINPUTconnector14ontherearpanel.
2. RemovethestopperfromthePANEL/REMOTE
controlselector13andsetthisto"REMOTE".
3.Thisisreadyforremotecontroloperation.Tuning
theremotecontrolswitchwillselecteitherofthe
threepresetvoltagesI,IIandMlandthevoltageset
bytheVOLTAGEcontrol7.
CAUTION• •
Formakingtheremotecontrolswitchbox
Usea 6-coreshieldedcable.Donotextenditlongerthan
2m. Besuretousea shortingtypeofswitch.
Fic/"""\5 """^iire6
10