Onan UF Series Instruction Manual

INSTRUCTION MANUAL
AND PARTS CATALOG
FOR
O
nan
GENERATORS
UF
SERIES
ALTERNATINGCURRENT-!PHASE-4WIRE
andI At
ALTERNATINGCURRENT-3PHASE-4WIREJ^F
REVOLVINGARMATURE
INHERENTLYREGULATED
ONAN140073RD
AVENUE N.E.• MINNEAPOLIS,MINNESOTA55432
A DIVISION OFSTUDBBAKER CORPORATION
-f^plrN.Y.INTERNATIONALOFFICE:EmpireStateBldg.
943-1
5AD70 Printed inU.S.A.

GENERAL INFORMATION
This instructionbookcontainsinformationfortheproperinstallation,
operation,andmaintenanceofyourequipment.We suggest thatthis
bookbekepthandysothatitcanbereferredtowhennecessary.
This equipmentistheresultofprovenengineeringdesign,hig;hest
quality materials,andexpert workmanship. Thoroughinspectionand
testingassuresyouthatthisequipment will performasexpected.
If youwishtocontactyourdealerorthefactoryregardingthisequip-
ment,besuretosupplythecomplete MODEL and SPEC. NO.,andthe
full serial numberoftheequipmentasshownonthenameplate. This
informationisnecessarytoidentifytheequipmentamongthemany
basic andspecialoptional types manufactured.
MANUFACTURER'S WARRANTY
TheManufacturerwarrants, tothe originaluser,thateachproduct of
its.manufacture'isfreefromdefects in material and factoryworkmanship
ifproperlyinstalled,serviced and operatedundernormalconditions
according tothe Manufacturer'sinstructions.
Manufacturer'sobligationunderthiswarranty is limited to correcting
withoutcharge atits factory any part or partsthereofwhichshall be
returned toits factory oroneofits AuthorizedServiceStations,trans-
portationchargesprepaid,within one yearafterbeing put intoservice
by the originaluser, and -whichuponexaminationshalldisclose tothe
Manufacturer'ssatisfaction to havebeenoriginallydefective.Correction •
ofsuchdefects by repair to,or supplying of replacements for defective
parts, shallconstitutefulfillment.of all obligations to originaluser.
Thiswarrantyshall not apply toanyofthe Manufacturer'sproducts
whichmust be replacedbecause of normalwear,whichhavebeensubject
tomisuse,negligence or accident or whichshallhavebeenrepaired or
alteredoutside ofthe Manufacturer'sfactoryunlessauthorized bythe
Manufacturer.
Manufacturershall hotbe liable for loss,damage or expensedirectly or
indirectlyfrom theuseofits product or from any othercause.
Theabovewarrantysupersedes andisin lieu of-all otherwarranties,
expressed or implied, andofall otherliabilities or obligations on part of
Manufacturer. No person,agent or dealer is authorized to give any
warranties on behalf ofthe Manufacturer norto assume forthe Manu-
facturer any otherliability in connectionwith anyofits productsunless
made in writing and signed byan officer ofthe Manufacturer.
DATED August 1,1963
IMPORTANT
RETURN WARRANTY CARD ATTACHED TOUNIT

5 TABLE OF CONTENTS
SUBJECT PAGE NO.
Description
Table ofRatings1
Generator2
Switchboards2
Installation
Location4
GeneratorCooling5
MountingtheGenerator5
Wiring Connections5
EnginePower; 5
EnginePulleySpeed6
PulleySelection6
1800RPMPulleySelectionTable7
1500 RPM PulleySelectionTable8
ReversingtheScroll. , 9
Operation
Starting10
Operating10
Maintenance
General Servicing,BrushandSpringRemoval11
Brush Contact, n
Brush RigNeutralPosition12
Major GeneratorRepair13
Disassembly13
Armature Grounded13
Testing.theArmatureforanOpen Circuit . 13
TestingtheArmatureforShortCircuits14
Field WindingsOpen Circuit 14
ServiceDiagnosis
PoorCommutationorArcingattheGeneratorBrushes.. 15
OverheatingofGenerator15
Generator Noisy 16
GeneratorRunsbut does notProduceCurrent16
Low VoltageOutputofGenerator: 16
Parts Catalog
InstructionsforOrderingRepairParts18
Parts Illustration19
Parts List 20
Wiring Diagrams22

DESCRIPTION
GENERATORTABLE OF RATINGS
GENERATOR GEN„ tPARTS
MODEL NO. CY. PH. WIRE VOLTS
WIRING
DIA. NO.
KEY
NO.
120/240
2e«UF-3*/J(^t 60 1 4
120/240
620B52 1
120/240
^UF-53^/^ 50 1 4
120/240
620B52 2
^UF-sl/l^llf
60 1 4
120/240
620 B 52 2
rD S
^UF-SSl^/l^P
50 1 4
120/240 620B52
3
^iuF-sl/itei^.
60 1 4
120/240
620B52
3
%UF-4M/l-ISt#
60 3
4 120/240
620B54 4
Note t - UsethePartsKeyNo.inthiscolumnforyourmodelwhen
selectingpartsfromthelistherein. Order only those parts
withnoPartsKeyNo.referenceor those partswhichrefer
tothePartsKeyNo.foryourmodel.
SWITCHBOARDTABLE OF RATINGS
SWITCHBOARD
MODELNO. * CYCLE PHASE
WIRE
VOLTS
CONTROL
WIRING
DIA. NO.
4SA-3/1A 50or60 1 4
120/240
615B84
5SA-3/1A 50 1 4 120/240
615B84
7SA-3/1A
60 1
4
120/240
615B84
* - ForallSwitchboardRepairPartsrefertothewiringdiagramfur-
nishedwiththecontrol.
NOTE: 120,240or 120/240 voltreferenceshereinapplyalsoto115,
230or 115/230 voltratings respectively.

DESCRIPTION
GENERATOR. - This generatorisinherentlyregulatedand will main-
tain theoutput voltage withinlimitsof 10% between no
loadand full load,whendrivenatitsnameplatespeedandatnormal
ambienttemperature.The voltage will besomewhathigherwhenthe
generatoriscold,and will vary withthedrivenspeed.Frequency will
vary 1 cycleforeach30rpmofvariationfromratedspeedaccording
tothecurvesbelow., % * -
CURVES OF VARIATION OF FREQUENCYWITHSPEED
*
c
y si
§ 50
5 49
LL,
E46
5 0 C'l CLI :GE ATO ST
62
o.
g»
u
g
60
I
59
K-
I* 58
6 3 CY CLE
CZl
JERJ LTOI
11
?
-
1440 1470
1500
SPEED IN RPM
1530 1560 1740 1770
Fig. 1. 1800
SPEED IN RPM
1830 1860
The powerfactorratingforallsinglephasemodelsis100%.Thepower
factorratingof3 phasemodelsis80%.The voltage regulation will not
begreaterthan10%at full loadandratedpowerfactor.
The generatormay*bedrivenineithera clockwise,prcounterclockwise
direction, asinstallationrequirementsdemand. - The blowerscroll
mustbereversedwheneverthegeneratorrotationischanged.See par-
agraph on REVERSINGTHESCROLL. Thegeneratorisshippedfrom
thefactorywiththescrollassembledforcounterclockwiserotation.
The directionofrotationofthegeneratorisdeterminedwhilelooking
attheendofthegenerator opposite tothedriveend.Thegeneratoris
drip proofindesign,butreasonableprecautionsshouldbetakenagainst
excessiveexposuretomoisture.
The instructionmanualcoversboth1 phase4 wire,and3 phase4 wire
ONAN Ball BearingSeparateGenerators.
A manualfieldrheostatcanbeusedwiththegeneratorifitisnecessary
tooperateaboveratedspeed.Itcanbeobtained,atadded cost after
thegeneratorisreceived.See "PARTS LIST" forcorrectpartnumber.
It canalsobeusedtoreducethe voltage atlightloads.Therheostat
can notbeusedtoincreasethe voltage abovewhatitwouldbewithout
it. Seewiringdiagramforproperconnections.
SWITCHBOARDS. - Switchboardsareoptionalequipmentwhichcanbe
purchased ataddedcost. Listed inthe TABLE OF
RATINGS aretheSwitchboardModelNo.'s.Theycontaina voltmeter,
ammeter,circuitbreaker,generatorandloadterminals.Theswitch-
board isgenerallyusedtocheckgeneratorandloadoperationaccurately
and topreventthegeneratorfrombeingoverloaded.Theoperatorcan

DESCRIPTION
checkthefollowing things byusinga switchboard:
(1)Generator voltage
(2) Load current
(3)Voltageregulationwithvaryingload
The circuitbreakerautomatically disconnects theloadfromthe gen-
eratorwhentheload exceeds thegeneratorkilowattratingbyapproxi-
mately25%.Whenthecircuitbreakertrips,itmustberesetmanually.
The causeoftheoverloadshouldbedetermined before resettingthe
breaker. Theloadcurrentvalueatwhichthecircuitbreakertripsis
affected somewhat bytheambienttemperature.Donotmountthe
switchboardina locationwhere excessive temperaturescan develop or
onsurfaceswhichvibrate.Excessivevibrationmayalterthetrip
current valueofthecircuitbreaker.
Whenorderingrepairpartsforswitchboards,obtain Part No's,and
descriptionofpartfromthewiringdiagramwhichissuppliedwiththe
switchboard.

INSTALLATION
LOCATION. - Selecta site forthegeneratorwiththefollowing points
in mind.
1.Ventilation.- Thegenerator will warmupandcreate some heat
whenoperatingunderloadconditions.Itisofvital
importancethatthisheatbedissipatedbyproperventilation.Ifthe
generatorisinstalledina smallroomorcompartment,providean
openingforentryoffresh,coolair.Providea separateopeningfor
exhaustingtheairheatedbythegenerator.Locatetheexhaustopening
above theinletopening,for best aircirculation.Heatedairisdis-
charged fromthedriveshaftendofthegenerator.
2. Convenienceto Driving Power.- Locatethegeneratoraftercon-
sidering thefollowingpoints:
A. Driving unitlocation.
B. Desireddirectionofshaftrotation.
C. Pulleyalignment,ifused.
D. Shaftalignmentofgeneratoranddrivingunitifa flexible
couplingisused.
A. Driving unitlocation.- Regardlessofthe type ofdrivingunitit
MUST beboltedsecurelytoa heavy
mountingbasetomaintainpulleyandshaftalignment.
B. Desireddirectionofshaftrotation.- Thedirectionofrotation
will bedeterminedbythe
direction ofrotationofthedrivingunit.Thegeneratordirectionof
rotationisreversibleandworksequallywellineitherdirection.
Howeverthegeneratorleadwiresandblowerscrollmustbeproperly
installed forwhateverdirectionofrotationisnecessary.Seewiring
diagram forproperleadconnections.Seeparagraphdn REVERSING
THESCROLL forproperscrollinstallation.
C. Pulleyalignmentifused.- Theshaftsofthegeneratorand
driving unitmustbeparalleland
the sides ofthepulleysmustbelinedup. Correct belttensionmust
bepermanentlymaintained.Afterthepulleysareinproperalign-
ment,bothgeneratoranddrivingunitmustbebolteddowntoa heavy
rigid mountingbase.
D. Shaftalignment.- Ifa flexiblecouplingisused,theshaftalign-
mentofthegeneratoranddrivingunitmust
beaccuratelymadeandpermanentlymaintained.Incorrectshaft
alignment will cause excessive wearonbothgeneratoranddriving
unit andunnecessary loss ofpowerfromthedrivingunit.

INSTALLATION
3. DustyorDampConditions.- Avoidexcessivedustyordampcon-
ditionsasmuchaspossible. Rust and
dirt are enemies ofanypieceofmachinery.Thegeneratorisdrip
proof indesign,butunnecessaryexposuretomoistureshouldbeavoided.
The generatorshouldbemountedundercoverorinsidea buildingto
protectitagainsttheweather.
4.ServicingConvenience.- Topermiteasyaccessforservicingthe
bearingsandbrushes,allowatleast24
inchesofspacearoundthegenerator.
5. Wiring Convenience.- Locatethegeneratorasnearaspossibleto
theelectricalequipmentitistoserve.
GENERATORCOOLING. - Thegeneratorblowersystem uses a revers-
ible scroll. Whentheblowerscrollisin-
stalledproperly,a strongflowofair comes outofthegeneratoratthe
generatordriveshaftend. Lack ofairflowindicatesimproperinstal-
lationoftheblower scroll. - Seeparagraphon "REVERSING THE
SCROLL".
MOUNTING THEGENERATOR. - Themountingsurfacemustbeflatso
thatthegeneratormountingbase will
notbesprung^whentightenedintoplace.Itshouldbepossibleto turn
thegeneratorshaftbyhandafterthegeneratorisbolteddown.
WIRINGCONNECTIONS. - Thegeneratorexternalleadsarenotcon-
nected,andtheirmannerofconnection will
dependuponwhethera rheostatistobeused,andthe DIRECTION OF
ROTATION. Refertothewiringdiagram.A rheostatoftheproper
sizeshouldbeinstalledifthespeedvariation will betoogreat,orifit
isnecessarytoreducethe voltage atlightloads.Theadditionofa
rheostat will notraisethe voltage abovethatwhichcouldbeobtained
withouttherheostat.A circuitbreaker between generatorandloadis
recommended.
Follow specificationsoflocalandnationalelectrical codes forinstall-
ingwiringandgroundingthegenerator.Besuretousewirelarge
enoughtoavoidexcessivedropin voltage between thegeneratorandthe
load, dependinguponthedistanceandtheamountoftheload.
The propersizeandtypeofdrivingunitforthegeneratorisimportant
forsatisfactoryoperationofthegenerator.Whena gasolineordiesel
engine isusedthefollowingfactorsshouldbeconsidered:
1.EnginePower.- The engine musthavea minimumof2 horsepower
foreach1000wattsofgeneratoroutput.Forex-
ample,ifa 5000 wattgeneratoristobeoperated,the engine must
deliver atleast10horsepoweratthedriveshaft.Ifthe engine hasa
considerablereserveofpowerthespeedregulationand voltage regula-
tion will bemuchbetter.
/

6 INSTALLATION
2. EnginePulley Speed. - Theenginemay have a variable speed gov-
ernor which regulatesengine speed atabout
8-1/2to12%.Ifso,governoroperationis best atthemaximumrated
speed oftheengine.Whenthegeneratorisoperatingator near its
capacity,thetendencyoftheengineisto increase speed whentheload
is suddenlyremoved.Theenginegovernor does notreactfastenough
atlow speed topreventmomentaryaccelerationand high voltage.This
maypossibly cause serious damage toanyelectricalequipment left
connected.Governoractionismuchbetterwhentheengineisoperat-
ing atitsrated speed, andtheenginecannot increase its speed too
much whentheloadisremoved.Iftheenginehasa constant speed gov-
ernor,the speed regulationis5%or less andtheaboveeffectsarenot
present.
Low generator speed causes lowvoltageandfrequency.If,forex^
ample,an1800rpmgeneratorisslowedto1500rpm,thefrequencyof
thecurrentproduced will be50cyclesinsteadof60cycles.Thecom-
bination oflowvoltageandfrequency will almostcertainlyresultin
burnedoutwindingsofanymotorsconnectedtothegenerator.
3.PulleySelection.- Therated speed oftheengineorelectricmotor
will determinethesizeofpulleytouseonthe
generatori,.Todeterminethecorrectgeneratorpulleysizetouse,pro-
ceedas follows, orrefertothe PULLEY SELECTION. TABLE.
A. Multiply the DIAMETER ofthe driving unit pulleybyitsSPEED
in rpm(revolutionsperminute).
B. Divide theaboveresultbythenameplate speed ofthegenerator
(1800rpm).
Example: A driving pulley15inchesindiameter operates at1200
rpm.. Multiply 15x 1200gettinga resultof18,000.
Divide the18,000by1800rpm(generatorpulley speed
desired)andthe final resultis10, which expresses the
Sizeofthepulley(ininches)required.Ifthis same
driving unit hasan8 inch pulleyoperatingat1200rpm
thegenerator pulley would thenbe5.33"orapproximately
5-3/8"(8x 1200, divided by1800= 5.33).

INSTALLATION
USETHIS TABLE ONLYFORGENERATORS STAMPED 1800 RPM ON
THE GENERATORNAMEPLATE.
The pulleysizesrecommendedinthistableareapproximatesizesonly,
in 1/2"steps.Thesizesshowndonotincludeanyallowanceforbelt
slippage.Beltslippageforflat belts may sometimes reducethegener-
ator drivenspeed,underload,asmuchas4 percent.
To selecta generatorpulleysizefromthetable,measurethe DIA-
METER (notthedistancearound)ofthedrivingpulley.Selecttheline
at theleftsideofthetableforthedrivingpulleysize.Followthisline
across tothespeedcolumnthatisnearesttotherecommendedspeedof
thedrivingpulley.Thesizeinthesquareatthispointistheapprox-
imatesizeofthegeneratorpulleywhich will berequired.Iftherecom^
mendedsizepulleycannotbeobtained,selectonesizesmallerpulley.
This will helpto offset beltslippage. Adjust throttleorgovernoras
necessary toobtainproperspeed.
Example:
If a 12inchdrivepulleyoperatesat1100rpm,followthe12inchline
across tothe1100rpmcolumn.Thegeneratorpulleysizeatthepoint
ofintersectionis7 inch. This exampleisoutlinedinheavylinesinthe
table.
DRIVING PULLEY SPEED IN REVOLUTIONSPERMINUTE
DRIVING
PULLEY
SIZE
600 700
GI
800900
:NERATO
ioooj^noQji20o|
R PULLEYSIZE 1
130o|
*EQU]
1400 j
RED
15001
^1800I
1600
R.P.N
1700
I. GEI
1800 1
JERA1
1900
[•OR)
2000
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