ASTM_D_1932_-_19.pdf

Designation:D193219Standard Test Method forThermal Endurance of Flexible Electrical InsulatingVarnishes1This standard is issued under the fixed designation D1932;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the relativethermal endurance of flexible electrical insulating varnishes bydetermining the time necessary at elevated temperatures todecrease the dielectric breakdown of the varnish to an arbi-trarily selected value when applied to a standard glass fiberfabric.1.2 This test method does not apply to varnishes that lose ahigh percentage of their dielectric breakdown voltage whenflexed before elevated temperature exposure as prescribed inthe screening test(Section 9).Examples of such varnishes arethose used for high speed armatures and laminated structures.Also,this test method is not applicable to varnishes whichdistort sufficiently during thermal elevated temperature expo-sure so that they cannot be tested using the curved electrodeassembly.1.3 Thermal endurance is expressed in terms of a tempera-ture index.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.NOTE1There is no equivalent IEC or ISO standard.1.5 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.For specific hazard statements,see Section 7.1.6 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:2D149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD374/D374M Test Methods for Thickness of Solid Electri-cal InsulationD580/D580M Specification for Greige Woven Glass Tapesand WebbingsD618 Practice for Conditioning Plastics for TestingD1346 Test Method for Testing Electrical Insulating Var-nishes for 180 C and Above(Withdrawn 1986)3D1711 Terminology Relating to Electrical InsulationD2307 Test Method for Thermal Endurance of Film-Insulated Round Magnet WireD2518 Specification for Woven Glass Fabrics for ElectricalInsulation(Withdrawn 2013)3D5423 Specification for Forced-Convection Laboratory Ov-ens for Evaluation of Electrical Insulation2.2 IEC Publications:IEC 60216 Guide for the Determination of Thermal Endur-ance Properties of Electrical Insulating Materials(Part 1)43.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method referto Terminology D1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 temperature index(TI),na number which permitscomparison of the temperature/time characteristics of an elec-trical insulating material,or a simple combination of materials,1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Products.Current edition approved Nov.1,2019.Published November 2019.Originallyapproved in 1967.Last previous edition approved in 2018 as D1932 18.DOI:10.1520/D1932-19.2For 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,25 West 43rd St.,4thFloor,New York,NY 10036.*A Summary of Changes section appears at the end of this standardCopyright 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.1 based on the temperature in degrees Celsius which is obtainedby extrapolating the Arrhenius plot of endpoint time versustemperature to a specified time,usually 20 000 h.3.2.2 thermal endurance graph,nan Arrhenius plot.3.2.3 therma