NIPPON--CHEMI-CON电解电容寿命算法

NIPPONCHEMI-CONCORPORATIONLifeTimeEstimationFormulaonKY/KZEseriesCapacitorsLx=Lox2(To–Tx)/10x2(∆∆∆∆To–∆∆∆∆Tx)/5=Lox2(105–Tx)/10x2(5–∆∆∆∆Tx)/5Where:Lx=Lifetime(hours)ofthecapacitortobeestimatedLo=Baselifetime(hours)ofthecapacitorshowninthecatalogTo=Maximumratedoperatingtemperature;105ºCforKY/KZETx=Actualambienttemperature(ºC)ofthecapacitorwithindevice(Thisisnottheenvironmenttemperatureofthedevice,buttheenvironmenttemperatureofthecapacitorthathasbeenplacedwithinthedevice.)∆To=Rise(ºC)incoretemperatureofthecapacitorduetorated(permissible)maximumripplecurrent.The∆∆∆∆TovaluesdesignedforKY/KZEare5ºCmaximumat105ºC.∆Tx=Actualrise(ºC)inthecoretemperatureofthecapacitorduetoactualripplecurrentatdeviceoperatingconditions.Tocalculatethe∆Txfromthesurfacetemperatureofthecapacitors,refertothetablebelow.∆∆∆∆Tx=(Ts-Tx)xKcWhere:Ts=Surfacetemperature(ºC)ofthealuminumcaseTx=Actualambienttemperature(ºC)ofthecapacitorKc=Coefficientstandingfortheratioofthe∆Txtothe(Ts-Tx)FortheKc’s,refertothetablebelow:Kc:Capacitordiameter(mm)φ5-φ8φ10φ12.5φ16φ18Kc1.101.151.201.251.30Also,tosimplyestimatethe∆Txfromtheactualrmsripplecurrent,usethefollowingequation:∆∆∆∆Tx=5x[(actualrmsripple)/(ratedrmsripple)]^2Theactualandratedmaximumrmsripplecurrentshallbeequaledinfrequencybyusingfrequencymultipliersprescribedforeachproductseriesinthecatalog.July2001byKohOhno---EngineeringofTaiwanChemi-Con