ASTM E780-2006 测量室温时绝缘矿物、铠装金属热电偶和热电偶电缆绝缘电阻的标准试验方法

作者:标准资料网 时间:2024-05-07 22:43:39  浏览:8356   来源:标准资料网

【英文标准名称】:StandardTestMethodforMeasuringtheInsulationResistanceofMineral-Insulated,Metal-SheathedThermocouplesandThermocoupleCableatRoomTemperature
【原文标准名称】:测量室温时绝缘矿物、铠装金属热电偶和热电偶电缆绝缘电阻的标准试验方法
【标准号】:ASTME780-2006
【标准状态】:现行
【国别】:
【发布日期】:2006
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E20.04
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:环境温度;绝缘电阻;材料;测量技术;温度测量;热电偶
【英文主题词】:insulationresistance;mineral-insulated,metal-sheathedthermocouplecableinsulationresistance;mineral-insulated,metal-sheathedthermocoupleinsulationresistance
【摘要】:Thermocouplesfabricatedfromthermocouplecablethathasbeencontaminatedbymoistureorbyotherimpuritiesmayundergolargechangesinthermoelectricpropertiesormayfailcatastrophicallywhenexposedtohightemperatures.Sincesuchcontaminationusuallylowerstheelectricalresistancebetweenthethermoelementsandthesheathsubstantially,measurementoftheinsulationresistancecanprovideavaluablecheckofinsulationqualityandcleanliness,andcanserveasabasisforrejectionofunsuitablematerialandunreliablecomponents.Formanufacturersinparticular,lowelectricalinsulationresistancecanalsobeindicativeofdisplacedthermoelementsordefectsinthemetalsheathwhichwillrequirefurtherinvestigation,butallusersshouldbeawareofthesepotentialdefectswhenfacedwithanunacceptableinsulationresistancemeasurement.Thistestmethodisprimarilyintendedforusebymanufacturersandusersofmineral-insulated,metal-sheathedthermocouplesorthermocouplecablestoverifythatmeasuredvaluesofinsulationresistanceexceedspecifiedminimumvalues,suchasthoselistedinSpecificationsE235,E585/E585M,E608/E608M,andE2181/E2181M.Manufacturersandusersshouldbeaware,however,thatwhentheinsulationresistanceisgreaterthan1x00D7;108x2126;,disagreementbyanorderofmagnitudeintheresultsobtainedwiththistestmethodisnotunusual.Inaddition,usersofthistestmethodshouldappreciatethattheroomtemperatureinsulationresistanceofboththermocouplecablesandoffinishedthermocouplesmaychangeduringshipment,storage,anduse,particularlyiftheendsealsaredamagedordefective.Consequently,valuesofinsulationresistancedeterminedbythistestmethodmaynotnecessarilyberepeatable.1.1Thistestmethodprovidestheproceduresformeasuringtheroomtemperatureelectricalinsulationresistancebetweenthethermoelements,andbetweenthethermoelementsandthesheath,ofamineral-insulated,metal-sheathedthermocoupleorthermocouplecable.Itmaybeusedtomeasuretheinsulationresistanceofbulklengthsofthermocouplecablepreviouslysealedagainstmoistureintrusionortotestathermocouplehavinganungroundedclass2junction.Thismethodcannotbeusedtotestathermocouplehavingagroundedclass1junctionunlessthejunctionisremovedpriortotesting,afterwhichthethermocouplemaybedealtwithinthesamemannerasathermocouplecable.1.2ThistestmethodappliesprimarilytothermocouplecablesconformingtoSpecificationsE585/E585MandE2181/E2181MandtothermocouplesconformingtoSpecificationsE608/E608MandE2181/E2181M,butmayalsobeappliedtothermocouplesorthermocouplecablesthataresuitableforuseinair,whosesheathorthermoelementsarecomprisedofrefractorymetals,thataretestedinadryandchemicallyinertenvironment,andthatmayemploycompactedceramicinsulatingmaterialsotherthanmagnesia(MgO)oralumina(Al2O3).Usersofthistestmethodshouldnotethatspecificationsdealingwithcompactedceramicinsulatingmaterialsotherthanmagnesiaoralumina,whicharedescribedinSpecificationE1652,arenotcurrentlyavailable.Asaresult,acceptancecriteriamustbeagreeduponbetweenthecustomerandsupplieratthetimeofpurchase,oralternatively,judgmentandexperiencemustbeappliedinestablishingtestvoltagelevelsandacceptableinsulationresistancevaluesforthesetypesofthermocouplesandthermocouplecables.1.3Thistestmethodmaybeusedforthermocouplesorthermocouplecableshavinganoutsidediameterof0.5mm(0.020in)orlarger.1.4Usersofthistestmethodshouldbeawarethattheroomtemperaturei......
【中国标准分类号】:K15
【国际标准分类号】:17_200_20
【页数】:5P.;A4
【正文语种】: