Sincro HB4 - Removal And Replacement Of Components And; Replacing the Bearings; Removal of the Main Rotor; Removal of the Rectifier Diodes

7.2 Removal and replacement of components
and component assemblies
The screws tightening torques for all reassembling
procedures are reported in the table of paragraph
6.2.4.
7.2.1 Replacing the bearings
Removal of the NDE bearing
• Unscrewthe4nutsthatfastenthebackshield
tothehousing.
• Disconnect the blackand redwires from theAVR
board.
• Hammertheshieldevenlyuntilitcomesaway
fromtherotor.
• Removethesnapring.
• Removethebearingusingastandardextractor.
• Takethenewbearingandheatitsoitsdiameterdilates
beforeslidingitintopositionontheshaft.
• Replacethesnapring.
• Positiontheshieldrememberingto insert the snap
ringandtthescrewsleavingthemloose.
• Hammertheshieldevenlyuntilthebearingandsection
ofhousingareinplace.
• Tightenthenutsontheshield.
Removal of the DE bearing
• Removethesnapring.
• Removethebearingorbearingsusingastandard
extractor.
• Takethenewbearingorbearingsandheatthem(max.
100÷110°C)sotheirdiameterdilatesbeforesliding
themintopositionontheshaft.
• Replacethesnapring.
• Inserttherotor.
Reassembly of bearings
Reassemblyofthebearingshouldbemadeinreverse
order of the operation described above taking in the
accountthefollowingcautions:
• Beforetting the bearing,ensure thatthe coupling
surfacesbothonthebearingandshafthasnosigns
ofwear;
• Heatthebearingtoapproximately80°Cbeforetting
itontotheshaft.
7.2.2 Removal of the main rotor
• Turntherotorinpositionthatthepolescenterlineis
inverticalposition;
• Dismount the shields(NDE andDE) from the
generatorsaspreviouslydescribed;
• Usingappropriatelysizedbelt,supporttheDEside
withitandcarefullystartwithtrackingtherotorout
ofthestator.Asrotorcomeoutofthestator,change
the position ofthe belt tillthe moment whenit’s
approximatelyonthegravitycenteroftherotor.During
thisprocess,it’snecessarytosupporttheNDEendof
therotortoguidetherotorpreciselyoutofthestatorto
avoidanydamagesofthestatorortherotorwinding.
Reassembly
Reassembly of the rotor should be made in reverse
order of the operation described above taking in the
accountthefollowingcautions:
• incasethattheanypartoftherotorischanged,the
completerotormustbere-balanced;
• in case ofsingle bearing alternators,check if the
couplingdiscsaredamaged.
7.2.3 Replacing the rotating diode bridge
• RemovetheshieldNDE,as7.2.1
• Onthe IB alternator, the replacementofthe diode
bridgecanalsobemadewithoutdisassemblingthe
NDEbearing,dismantlingthebearinghowevermakes
theoperationeasier.
• OntheHBalternator,itisnotnecessarytoremove
thebearing
• ForHB:disconnectthe3wiresoftheexciterrotorand
thetwowiresofthemainrotor,markingtheposition
ontheterminalboard
• ForIB: removethe3-way connectorand the two
fast-on.
• Loosenthelockscrewandremovethediodebridge
Toreplacethediodebridge,proceedbackwards:
• Fixthebridgewiththelockingscrewandthreadlock
• Restoretheoriginallinks,respectingthepolarity
• Replacethebearingshieldandprotectivegrid
7.2.4 Replacing the fan
• Uncouplethealternatorfromthedrivemotor
• RemovetheshieldDEside(inthecaseofmounting
IMB34)
• Thefanislockedontheshaftthroughakey(1).Loose
thescrew(2),withoutremovingit,andthenhitthe
screwheadwithahammer.Thiswillallowthetongue
tomoveinsidetheangleseat,freeingthefan.
• Before removing thefan, mark thelocation of the
washers(mountedonthefanitself)usedforbalancing
• Thenremovethescrewandremovethefan
Toreplacethefanproceedbackwards:
• Placetheshaftkey(1)inthekeyseat
• Insertthefan(byhand,orwiththehelpofarubber
hammer)
• Insertthescrew(2),screwitintothetab(withthread
lock)andtightenitfollowingthetorquevaluesshown
inparagraph6.2.4
• Replacethe balancingwashersin their original
position(makesurethattheyarelocked)
7.2.5 Changing rotor exciter
• RemovetheshieldNDE,as7.2.1
• RemovethebearingNDE
• Disconnectandremove the rotatingdiode bridge
(see7.2.3)
• Theexciterrotorislockedtotheshaftthroughakey
(1).Loosethelockscrew(2),withoutremovingit,
andthenhitthescrewheadwithahammer.Thiswill
allowthekeytomoveinsidethekeyseat,inorder
tofreetheexciterrotor.
• Removethescrewandremovetheexciterrotor.
Toreplacetheexciterrotorworkbackwards:
• -Placethekey(1)initsseat
Incaseofregreasablebearing,followthe
procedure as described above, taking
into account to place back additional
mechanical parts used for bearing
lubrication in thesame position likethey
were prior to dismounting. Apply the
quantityandtypeof grease as indicated
onthegeneratornameplate.
IMPORTANT!
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