Danfoss TTS350

Motor/System
Status Description
Trigger
Method
Troubleshooting
RotorStarting
TorqueFault
INS
l
Atlowspeed(startup)rotorangularpositionisnotatcorrectvalueforagivenspeed,causedbylow
shaftmagnetstrength,liquidfloodedcompressorordamagedtouchdownbearings/physicalcontact
ofrotatingcomponents.
l
Ifthisfaultoccursthreetimeswithina30-minuteperiod,aLock-OutFaultwilloccur.
l
IffaultoreventlogsshowoccurrenceofStartingTorquefaultafteroneInverterError,theInverter
shouldbeverifiedandmayrequirereplacement.RefertoInverterErroronpage260orMotor
SinglePhaseOvercurrentFaultonpage260.Shaftorbearingsmaybemechanicallydamagedand
unabletoturn.
l
Verifythebearingcalibrationandlevitation.RefertoSection5.3BearingCalibrationonpage263.
l
VerifytheInverter.RefertoSection4.22.2InverterVerificationonpage176.
l
VerifytheStator.RefertoSection4.23.4MotorVerificationonpage195.
l
ReviewFaultandEventLogdetailstodetermineconditionsrelatedtothefault.
LowInverter
CurrentFault
AFT
l
Suggeststhecompressorhasnoload,verifyloadisavailable.Minimummagnetizingpowernot
absorbedforgivenspeedattheInverter.
l
Compressorisnotpumpinggas.Usuallyseeninopen-airoperation.
l
ReviewtheFaultLogforthelevelofMotorCurrentinthefaultrecord.
l
ZeromotorcurrentatzeroRPMindicatesaproblemwiththeInverter.VerifytheInverter.Referto
Section4.22.2InverterVerificationonpage176.
l
VerifytheStator.RefertoSection4.23.4MotorVerificationonpage195.
DCBus
Under/Over
VoltageFault
DFT
l
At0RPM:IfthemeasuredDCBusvoltageislowerthanSoftStartchargevoltage,aDCbusvoltage
faultisrecorded.All3-phasevoltageinformationdisplayedintheSMTiscalculatedfromDCbus
voltage,asmeasuredbytheInverter.
l
Typically,thisfaultisrecordedwhenpowertothecompressorisremoved.
l
MeasureandcomparetheincomingmainACvoltagetothecompressorratedvoltage.
l
ComparethemeasuredvoltagestothedisplayedreadingsintheCompressorMonitorToolandFault
andEventLogdetailstodetermineconditionsrelatedtothefault.
l
MeasuretheDCbusvoltageusingtheDCBusTestHarness.RefertoSection1.10.1General
VerificationandInstallationoftheDCBusTestHarnessonpage26.
l
VerifytheSoftStart.RefertoSection4.14.2SoftStartVerificationonpage115.
l
VerifytheSCRs.RefertoSection4.18.2SCRVerificationonpage142.
l
VerifytheconnectionstotheInverter.RefertoSection4.22.2InverterVerificationonpage176.
24VDC
Under/Over
VoltageFault
RFT
l
Suggeststhemeasured24VDCsupplyvoltageisoutofrange.
l
Measurethe24VDCtestpointsattheBackplane.RefertoSection4.25.2.2BackplaneVerificationon
page214.
l
ComparethemeasuredvoltagestothedisplayedreadingsintheCompressorMonitorToolandFault
andEvent
l
ReviewFaultLogdetailstodetermineconditionsrelatedtothefault.
l
Ifthemeasuredvoltageisincorrect,verifytheDC-DCConverter.RefertoSection4.24.2DC-DC
ConverterVerificationonpage204.
l
Determinethatoneofthemodulesisnotdrainingenergy.RefertoSection5.5.2Determiningthe
CauseofanEnergyDrainonpage271.
l
Ifthefaultoccurswhenthecompressorisgiventhedemandtorun,theInvertermaybecausingthe
24VDCfault.
LowMotorBack
EMFFault
DFT
l
Thecalculatedmagneticstrengthoftheshafthasfallenbelowtheminimumlimit.Thiscanbea
temporaryeffectduetohighloadandelevatedtemperatures(willrecoverwhencavitytemperature
cools)orduetoapermanentdemagnetizationoftheshaft.
l
Ifthisfaultoccursthreetimeswithina30-minuteperiod,aLock-OutFaultwilloccur.
M-SV-001-EN Rev. H-1/23/2023 Page 261 of 294