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Elevator Machine Room Maintenance exam with correct answers
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Elevator Machine Room Maintenance examwith correct answers
Bearings nn- nncorrect nnanswer-Bearings nnare nnmechanical nnassemblies nnthat nnconsist nnof nnrolling nnelements
nnand nnusually nninner nnand nnouter nnraces nnwhich nnare nnused nnfor nnrotating nnor nnlinear nnshaft nnapplications,
nnand nnthere nnare nnseveral nndifferent nntypes nnof nnbearings, nnincluding nnball nnand nnroller nnbearings, nnlinear
nnbearings, nnas nnwell nnas nnmounted nnversions nnthat nnmay nnuse nneither nnrolling nnelement nnbearings nnor nnplain
nnbearings.
Ball nnBearings nn- nncorrect nnanswer-Ball nnBearings nnare nnmechanical nnassemblies nnthat nnconsist nnof nnrolling
nnspherical nnelements nnthat nnare nncaptured nnbetween nncircular nninner nnand nnouter nnraces. nnThey nnprovide nna
nnmeans nnof nnsupporting nnrotating nnshafts nnand nnminimizing nnfriction nnbetween nnshafts nnand nnstationary
nnmachine nnmembers. nnBall nnbearings nnare nnused nnprimarily nnin nnmachinery nnthat nnhas nnshafts nnrequiring
nnsupport nnfor nnlow nnfriction nnrotation. nnThere nnare nnseveral nnconfigurations, nnmost nnnotably nnshielded nnor
nnsealed. nnBall nnbearings nnare nnstandardized nnto nnpermit nninterchangeability. nnBall nnbearings nnare nnalso
nnknown nnas nnrolling nnelement nnbearings nnor nnanti-friction nnbearings. nnConsiderations nninclude
First nnchoice nnfor nnhigh nnspeeds nnor nnhigh nnprecision nnapps
Large nnrange nnof nnstandardized nnforms
Handle nnradial nnand nnaxial nnloads nnwith nnspecific nnconfigurations
Roller nnBearings nn- nncorrect nnanswer-Roller nnBearings
Roller nnBearings nnare nnmechanical nnassemblies nnthat nnconsist nnof nncylindrical nnor nntapered nnrolling
nnelements nnusually nncaptured nnbetween nninner nnand nnouter nnraces. nnThey nnprovide nna nnmeans nnof
nnsupporting nnrotating nnshafts nnand nnminimizing nnfriction nnbetween nnshafts nnand nnstationary nnmachine
nnmembers. nnRoller nnbearings nnare nnused nnprimarily nnin nnmachinery nnwith nnrotating nnshafts nnthat nnrequire
nnthe nnsupport nnof nnheavier nnloads nnthan nnball nnbearings nnprovide. nnTapered nnroller nnbearings nnare nnoften
nnused nnto nnaccommodate nnhigher nnthrust nnloads nnin nnaddition nnto nnthe nnradial nnloads. nnTypes nnrange nnfrom
nncylindrical nnto nnspherical nnrollers. nnRoller nnbearings nnare nnstandardized nnlike nnball nnbearings, nnalbeit nnto nna
nnlesser nndegree. nnConsiderations nninclude
Higher nnload nncapacities nnthan nnball nnbearings
Can nnwithstand nnhigh nnaxial nnloads
Sleeve nnBearings nn- nncorrect nnanswer-Sleeve nnbearings nnhave nna nnhigher nncoefficient nnof nnfriction nnthan nnball
nnand nnroller nnbearings. nnSleeve nnbearings nncan nnsupport nnheavy nnradial nnloads. nnSleeve nnbearings
, nn(sometimes nncalled nnbushings, nnjournal nnbearings nnor nnplain nnbearings) nnfacilitate nnlinear nnmovement
nnbetween nntwo nnparts. nnSleeve nnbearings nnconsist nnof nna nnmetal, nnplastic nnor nnfiber-reinforced nncomposite
nnsleeves nnthat nnreduce nnvibrations nnand nnnoise nnby nnabsorbing nnfriction nnbetween nntwo nnmoving nnparts
nnusing nna nnsliding nnmotion.
MG nnSET nn- nncorrect nnanswer-A nnmotor nngenerator nn(M-G) nnset nnrefers nnto nna nncomposite nndevice
nnconsisting nnof nna nnmotor nnand nna nngenerator nnmechanically nncoupled nnthrough nnthe nncommon nnshaft.
nnPractically nna nnmotor nngenerator nnset nnis nna nnsystem nnwhere nna nnmotor nnand nna nngenerator nnare
nnconnected nnor nnrather nnplaced nnin nna nnsingle nncircuit.
Rotating nnExciter nn- nncorrect nnanswer-Some nnmotor nngenerator nnsets nninclude nnan nnexciter nnthat nnis
nnmounted nnon nnthe nnsame nnframe nnas nnthe nnmain nngenerator. nnIts nnjob nnis nnto nnprovide nnDC nnpower nnfor
nnoperation nnof nnmost nnof nnthe nnrelays nnin nnthe nncontroller, nndoors, nnbrake, nnand nnfields. nnRotating nnExciters
nnare nnreplaced nnwith nnSolid nnState nnExciters nnon nnmodern nnequipment. nnMost nnof nnthe nnmaintenance
nnitems nnoutlined nnfor nnthe nnmain nngenerator nnapply nnto nnthe nnexciter. nnThe nnmajor nndifferences nnare nnthe
nnsize nnand nnmethod nnof nnfield nnexcitation. nnThe nnoutput nnof nnthe nnexciter nnis nn125 nnor nn230VDC nnin nnthe
nnrange nnof nn2 nnto nn5KW nndepending nnon nnthe nnDC nnrequirements nnof nnthe nnelevator.
Governors nn- nncorrect nnanswer-An nnoverspeed nngovernor nnis nnan nnelevator nndevice nnwhich nnacts nnas nna
nnstopping nnmechanism nnin nncase nnthe nnelevator nnruns nnbeyond nnits nnrated nnspeed. nnThis nndevice nnmust nnbe
nninstalled nnin nntraction nnelevators nnand nnroped nnhydraulic nnelevators. nnThis nndevice nnwas nnfirst nnpatented
nnby nnWarner nnElevator nnMfg nnCompany nn(Patent nnno.: nnUS1549736[1]) nnthen nnOtis nn(Patent nnno.:
nnUS3327811[2]). nnAll nnare nnrequired nnto nnbe nnmanually nnreset.
Governors nnCont. nn- nncorrect nnanswer-There nnare nntwo nnmajor nntypes nnof nngovernors: nncentrifugal nnand nnthe
nnflyball nntypes. nnThe nncentrifugal nntype nnis nnused nnfor nnall nnspeed nnapplications nnwhereas nnthe nnflyball nntype
nnis nnusually nnfound nnon nnolder nnhigh-speed nnapplications. nnFor nnsafety, nnthe nncentrifugal nntype nnmay nnhave
nnall nnof nnits nnmoving nncomponents nncovered nnby nna nnmetal nnenclosure. nnThe nnflyball nntype nnhas nnexposed
nnmoving nnparts nnthat nncan nnbe nnhazardous.
Governors nnCode nn- nncorrect nnanswer-The nnmechanical nntripping nnspeed nnof nnthe nngovernor nnis nndefined nnby
nnA17.1 nn2001 nn2.18.2.1 nnand nnstates nnthat nnthe nnminimum nntripping nnspeed nnto nnbe nnnot nnless nnthan nn115%
nnof nnthe nnrated nnspeed. nnBefore nnthe nnsafety nnis nninitiated nnthere nnare nnelectrical nncontacts nnthat nnare
nnactuated nnto nnstop nnthe nncar. nnThis nnswitch nnshall nnnot nnopen nnat nnmore nnthan nn90% nnof nnthe nnmechanical
nntripping nnspeed nnat nnwhich nnthe nngovernor nnis nnset nnto nntrip. nnFor nnrated nnspeeds nnabove nn500 nnFPM nnthe
nnswitch nnshall nnopen nnat nnnot nnmore nnthan nn95% nnof nnthe nnmechanical nntripping nnspeed
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