风扇寿命表格FS1240-A3012A---MTTF

ModelNo.TestConditionInputVoltage12VDCElectricalSpecificationSpeed4000RPMTestTemp.70℃Current0.09AmpDirectionVertical43,429HoursBearingSystemStartDate8/2'084,576HoursTestSample(pcs)FinishDate11/3'08TestHours/EachOver2000TotalTestHoursAccu.F/OTTF(Hours)UUT(pcs)Accu.F/RMTTFTestResultAF：AccelerationfactorforcalculatingMTTFatdifferenttemperature.(MIL-STD-781C)AF=2^﹝(Ta–Tu)/10﹞Ta：Testtemperature,Tu：ReferencetemperatureMTTF=mL1XAFThefollowingprodureexplainsthederivationofL10Pointestimates,confidenceintervals,predictionintervalsandtoleranceintervalsmL1:Lowerone-sidedlimitforthemeantimetofailure(MTTF)mL1=1-α:ConfidenceLevel(90%)T*:Theaccumulatedtesttimer:NumberofFailure(2r+2):DegreeofFreedomX21-α（2r+2）:Tablesofthefractilesoftheχ2distributionThe（L10）L1atalowerone-sided90﹪confidenceonMTTFis(L10）L1=【-ln（0.9）】XmL1Temp(℃).30℃40℃50℃55℃60℃63℃70℃MTTF694,864347,432173,716130,28786,85870,55043,429L1073,21136,60518,30313,7279,1517,4334,576CalculationReferTo:IEC60605-4：2001,EQUIPMENTRELIABILITYTESTING–Part4：StatisticalproceduresforREV:A01Approved:GuangyiChaiChecked:GuangyiChaiTested:XiaoyanCui3.Fannotrunexponentialdistribution–Pointestimates,confidenceintervals,predictionintervalsandtoleranceintervals.100000TotalTestHours=50X2000=100000HoursGetMTTFat70℃GetL10at70℃TheEstimatedMTTF=100000/2.3026=43429Hours(IEC-60605-4:2001section5.1)ACT-RXTechnologyCorporationMTTF&L10LifeTestReportCeraDynaA50FS1240-A3012ANumberofFailureConfidenceLevel090﹪FailureCriteriaRemark:othercompetitorsfailurecriteria-30%Checkpointatthehoursof0,250,500,750,1000,1500,2000…TestResult:(TTF:TimeToFailure;UUT:UnitUnderTest;F/R:FailureRate,Datum,Stastics…etc.)Failuremode2.Current:Over15%oforiginalvalue1.Speed:Under15%oforiginalvalue2T*2T*2T*χ21-α（2r+2）