Danfoss TTS400

Motor/System
Status Description
Trigger
Method
Troubleshooting
l
ComparetheBackEMFvaluetothedisplayedreadingsintheCompressorMonitorToolandFault
andEventLogdetailstodetermineconditionsrelatedtothefault.
l
PermanentdamagetoBackEMFcanbecausedbyinsufficientmotorcooling,repeatedoverheating
ofcavity,faultyInverter,faultyBMCC,repeatedRotorStartingTorqueorSinglephaseOver-Current
faults.RefertoInverterErroronpage260.
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.
GeneratorMode
Active
DFT
l
Indicates,atgreaterthan0RPM,themeasuredactualDCBusvoltagehasfallenbelowtheGenerator
ModeEnabledLevelvalue.Also,couldbeelectronic“noise”whennoactualdropinvoltagehas
occurred.
l
MeasuretheincomingmainACvoltage.
l
MeasuretheDCbusvoltageusingtheDCBusTestHarness.
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
Typically,thisfaultisrecordedwhenpowertothecompressorisremovedwhileitisrunning.
EEPROM
ChecksumFault
INS
l
IndicatesthereisanerrorreadingtheEEPROMintheBMCC.
l
PerformabearingcalibrationandsavetoEEPROM,cyclethepower.
l
Iftheerrorisstillpresent,theBMCCmustbereplaced.
SCRRipple
VoltageFault
AFT
l
SuggeststhatavoltageorcurrentimbalancemayexistbetweentheincomingACphasestothe
SCRs.
l
MeasurethedifferenceincurrentandvoltagebetweentheACphases.
l
Ifthereisacurrentimbalance(morethan5%)betweenthephases,verifytheincomingACpower
supply.
l
ReviewtheCompressorMonitorToolforSCRVoltageRipplereadingsatthetimeofthefault.
l
PhaseimbalancecanalsobecausedbyafaultySCR,SCRGate,GatecontrolfromtheSoftStart
Board,orafaultypowercapacitor.
l
VerifytheSCRs.RefertoSection4.18.2SCRVerificationonpage142.
l
VerifytheSoftStartBoard.RefertoSection4.14.2SoftStartVerificationonpage115.

Page 262 of 294 - M-SV-001-EN Rev. H 1/23/2023