ASTM_D_5374_-_22.pdf

Designation:D537422Standard Test Methods forForced-Convection Laboratory Ovens for Evaluation ofElectrical Insulation1This standard is issued under the fixed designation D5374;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover procedures for evaluating thecharacteristics of forced-convection ventilated electrically-heated ovens,operating over all or part of the temperaturerange from 20 C above the ambient temperature to 500 C andused for thermal endurance evaluation of electrical insulatingmaterials.1.2 These test methods are based on IEC Publication 60216-4-1,and are technically identical to it.This compilation of testmethods and an associated specification,D5423,have replacedSpecification D2436.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D2436 Specification for Forced-Convection Laboratory Ov-ens for Electrical Insulation(Withdrawn 1994)3D5423 Specification for Forced-Convection Laboratory Ov-ens for Evaluation of Electrical Insulation2.2 Other Document:IEC Publication 60216-4-1 Guide for the Determination ofThermal Endurance Properties of Electrical InsulatingMaterials,Part 4Aging Ovens,Section 1Single-Chamber Ovens43.Terminology3.1 Refer to the terminology section of SpecificationD5423.4.Significance and Use4.1 Ovens used for thermal evaluation of insulating materi-als are to be capable of maintaining uniform conditions oftemperature and air circulation over the extended periods oftime that are required for conducting these tests.SpecificationD5423 specifies the permissible variations from absoluteuniformity that have been accepted internationally for theseovens.These test methods include procedures for measuringthese variations and other specified characteristics of the ovens.5.Apparatus5.1 Multi-Point Recording Potentiometer,having provisionsforatleastnineiron-constantanorchromel-alumelthermocouples,with scale readings to 0.1 C or less.Use of adata processor or a data logger is helpful in reducing thenumber of calculations required.5.2 CalibratedIron-ConstantanorChromel-AlumelThermocouples,using 0.5-mm diameter or smaller wire andhaving a junction size not over 2.5 mm long.5.2.1If calibrated thermocouples are not available,usethermocouples made from a single spool of thermocouple wirethat gives values for temperature that do not differ from eachother by more than 0.2 C when placed within 10 mm of eachother without touching inside an oven chamber at 200 C.5.3 It is acceptable to use a temperature measuring systemother than thermocouples and a potentiometer,provided thatthe sensitivity,accuracy,and response time are equivalent to1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct responsibility ofSubcommittee D09.17 on Fire and Thermal Properties.Current edition approved Jan.1,2022.Published February 2022.Originallyapproved in 1993.Last previous edition approved in 2013 as D5374 13.DOI:10.1520/D5374-22.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1that of the equipment described above,and that the objectivesof 6.2.3 relative to minimization of heat conduction effects aremet.5.4 Thermal Lag Time Specimen,consisting of a solid brasscylinder,10 mm in diameter and 55 mm long,with onejunction of a differential thermocouple soldered to the surfacemidw