ASTM_D_1932_-_13.pdf

Designation:D193213Standard 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 and health practices and determine the applica-bility of regulatory limitations prior to use.For specific hazardstatements,see Section 7.2.Referenced Documents2.1 ASTM Standards:2D149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD374 Test Methods for Thickness of Solid Electrical Insu-lation(Withdrawn 2013)3D580 Specification for Greige Woven Glass Tapes andWebbingsD1346 Test Method for Testing Electrical Insulating Var-nishes for 180 C and Above(Withdrawn 1986)3D1711 Terminology Relating to Electrical InsulationD2518 Specification for Woven Glass Fabrics for ElectricalInsulation(Withdrawn 2013)3D5423 Specification for Forced-Convection Laboratory Ov-ens for Evaluation of Electrical InsulationD6054 Practice for Conditioning Electrical Insulating Mate-rials for Testing(Withdrawn 2012)32.2 IEEE Publications:4IEEE No.101A Guide for the Statistical Analysis of Ther-mal Life Test Data(including Appendix A)2.3 IEC Publications:IEC 60216 Guide for the Determination of Thermal Endur-ance Properties of Electrical Insulating Materials(Part 1)53.Terminology3.1 Definitions: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 Varnishes,Powders and Encapsulat-ing Compounds.Current edition approved April 1,2013.Published April 2013.Originallyapproved in 1967.Last previous edition approved in 2009 as D1932 04(2009).DOI:10.1520/D1932-13.2For 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 the Institute of Electrical and Electronics Engineers,1828 L St.,NW,Suite 1202,Washington,DC 200365104.5Available 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 States1 3.1.1 temperature index(TI),na number which permitscomparison of the temperature/time characteristics of an elec-trical insulating material,or a simple combination of materials,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.3.1.2 thermal endurance graph,nan Arrhenius plot.3.1.3 thermal endpoint time,nthe time necessary for aspecific property of a material,or a simple combination ofmaterials,to degrade to a defined end point when aged at aspecified temperature.3.1.4 thermal life endpoint time,na graphical representa-tion of thermal endpoint time at a specified exposure tempera-ture in which the value of a property of a material,or a simplecombination of materials,is measured at room temperature andthe values plotted as a function of time.3.1.5 Refer to Terminology D1711 for definitions of otherterms.4.Su