1、Designation:D251919aStandard Test Method forBond Strength of Electrical Insulating Varnishes by theHelical Coil Test1This standard is issued under the fixed designation D2519;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year o
2、f 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 determinati
3、on of the bondstrength of an electrical insulating varnish when applied to ahelical coil.The helical coil can be made from bare aluminumor copper wire or from film or fiber-insulated magnet wire.Helical coils made from bare aluminum or bare copper wirewill yield values of bond strength for the varni
4、sh when appliedto bare metal conductors.The use of film or fiber-insulatedmagnet wire will show values for that particular combinationof insulation and varnish.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standar
5、d 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.See Section 7.1.4 Th
6、is 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(
7、TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D115 Test Methods for Testing Solvent Containing Var-nishes Used for Electrical InsulationD1711 Terminology Relating to Electrical InsulationD6054 Practice for Conditioning Electrical Insulating Mate-rials for Testing(Withdrawn 2012)3E691 Pract
8、ice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method referto Terminology D1711.3.1.2 bond strengtha measure of the force required toseparate surfaces which have been bonded together.
9、3.2 Definitions of Terms Specific to This Standard:3.2.1 event timethe time between initial application of aphysical or electrical stress and failure of the specimen undertest.3.2.2 response timethe time required for an indicating orrecording device to react to change in stress on a specimenunder te
10、st.3.2.3 varnish,electrical insulating,na liquid resin systemthat is applied to and cured on electrical components providingelectrical,mechanical,and environmental protection.3.2.3.1 DiscussionThere are two types of electrical insu-lating varnish:solvent-containing and solventless.The solvent-contai
11、ning varnish is a solution,dispersion,or emulsion of apolymer or mixture of polymers in a volatile,nonreactableliquid.The solventless type is a liquid resin system free ofvolatile,nonreactable solvents.4.Summary of Test Method4.1 Flexural strength tests are made on varnish-treatedhelical coils to de
12、termine the force required to break the coilunder specified conditions.5.Significance and Use5.1 Values obtained by flexural tests can provide informa-tion with regard to the bond strength of the particular varnish,1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and El
13、ectronic 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 1966.Last previous edition approved in 2019 as D2519 19.DOI:10.1520/D2519-19A.2For referenced ASTM
14、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.*A
15、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
16、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 in combination with a particular wire,when measured underconditions described in this test method.6.Apparatus6.1 Tensile Testing MachineUse an adjustable-speed driveand a suitable instrument for measuring force to break thespecimen.Available tensile testing machines or an accuratespring gauge and a separate adjus
