Franklin Q-link - Page 98

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Fault Cause
 Remedy
UnderVoltage(L) AVFD undervoltagefault
occurswhentheVFD’s
internalDCbusvoltagelow
limithasnotbeenmet.

 Checkthatthemeasuredline
voltagematchestheVFDrated
nominalvoltage
 Checkyourmotorwiring
 ChecktheVFD’sDCbusvaluebefore
runningamotorandwhilerunni nga
motor.Ifthevoltagedropsaftera
motorloadhasbeena
pplied,there
maybeamotorissue.
 Disconnectthemotorwiresatthe
VFD,disablethenomotor
protectioninPROTECTION‐03,and
runtheVFDwithnoload.Ifproblem
persists,thentheVFDmayhave
internaldam
age.
 Checkthemotorwithamegger
meter.Ifthemotortestsfine,the
VFDworksfinewithnoload,and
theDCbusstilldropswhenaloadis
applied,checkthelinevoltageto
seeifitmaybeanoverloadedutility
transformercausingtheissue.Ifthe
linevoltageisfine,conside
r
replacingtheVFD.
InputPhaseOpen(L) Occurswhen:Theamplitude
ofDCbusripplesexceedsa
setvalue.

 Ensureallwiresoftheinput(R,S,
andT)areproperlytorqued.
 EnsuretheVFDisreceivingproper
inputVoltagetoeachphase.
 Ensuretheutilitypowertransformer
isproperlysizedforVFDload.
OutputPhaseOpen
(L)
Occurswhen:Anyofthe
outputphases(U,VorW)
hascurrentlessthanthe
OutputPhaseOpenLevel
(Protect‐19).
 CheckcontactoratVFDoutput.
 Checkoutputwiring(U,V,andW)
fromVFDtomotor.
 Checkmotordisconnectifinstalled

NoMotor(L) Occurswhen:Allthree
phaseshavecurrentbelow
15%ofmotorFLAfor250ms.
Motorcircuitisopenorhas
looseconnection.

 EnsureMotorwiresareproperly
torquedandwiredtoU,V,andW.
 Ensureoutputdisconnectisturned
oneifadisconnectisinstalled
betweenVFDandMotor.
 IftheVFDisbeingtest edwithouta
motor,ensureProtect‐03isNo.

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