1、Designation:D488018Standard Test Method forSalt Water Proofness of Insulating Varnishes OverEnamelled Magnet Wire1This standard is issued under the fixed designation D4880;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of l
2、ast revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers the electrical performance in aspecified water solution of an insulating varnish applied overenamel
3、led magnet wire.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.3 This standard does not purport to address all of thesafety conce
4、rns,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.Specific precautionary statements are given in Section 6.NOTE1There is n
5、o IEC method equivalent to this standard.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
6、 Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1676 Test Methods for Film-Insulated Magnet WireD1711 Terminology Relating to Electrical Insulation3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method referto Term
7、inology D1711.3.1.2 varnish,electrical insulating,n a liquid resin systemthat is applied to and cured on electrical components providingelectrical,mechanical,and environmental protection.3.1.2.1 DiscussionThere are two types of electrical insu-lating varnish solventcontaining and solventless.Thesolv
8、ent-containing varnish is solution,dispersion,or emulsionof a polymer or a mixture of polymers in a volatile,nonre-actable liquid.The solventless type is a liquid resin system freeof volatile,nonreactable solvents.3.1.3 varnished,adjreferring to any item on to whichvarnish has been applied and cured
9、.4.Significance and Use4.1 This test method is useful in determining the perfor-mance of varnishes over enamelled magnet wire when sub-jected to the specified sodium chloride solution.It is useful inevaluating the resistance of varnished magnet wire to a dilutedsodium chloride solution under applied
10、 voltage.5.Apparatus5.1 Description of Electrical Apparatus:5.1.1 The apparatus shall contain devices for limiting orinterrupting the current to each specimen whenever a failureoccurs.In particular,7.5 W light bulbs or110Afuses have beenused.Lighting of the bulb or“blowing”of the fuse indicatesfailu
11、re.5.1.2 The power supply shall provide a source of filtered120 6 2 V dc which drops by less than 2 V when a current of0.5 A is drawn.5.1.3 A positive polarity of 120 V dc is applied to thespecimens.The surrounding sodium chloride solution is atground potential.The ground connection,using an immerse
12、delectrode,is made using Nichrome,stainless steel,or othernon-corrosive wire.Do not use iron,carbon steel,copper,orbrass(see Figs.1 and 2).5.2 An appropriate container shall be selected for thesodium chloride solution.Fit it with a cover to preventevaporation of the solution.6.Safety Precautions6.1
13、Do not use varnish at temperatures above the flash pointwhen inadequate ventilation,and possibility of flames or1This 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 Insu
14、lating Products.Current edition approved Nov.1,2018.Published November 2018.Originallyapproved in 1988.Last previous edition approved in 2014 as D4880 14.DOI:10.1520/D4880-18.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Ann
15、ual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*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
16、 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 sparks exist.Store varnish in sealed containers.These precau-tions shall also apply to the handling of the reagents andsolvents called for in this test method.6.2 WarningLethal voltages are a potential
