ASTM_D_3955_-_20.pdf

Designation:D395520Standard Specification forElectrical Insulating Varnishes1This standard is issued under the fixed designation D3955;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.Scope*1.1 This specification covers the tests and values for elec-trical insulating varnishes,as supplied,which are suitable forthe impregnation and treatment of electrical coils and windingsapplied by dip process.1.2 Varnishes,flexible or rigid,included in this specificationare:Grade DAAir-dryGrade DOOrganic solvent containing,baking,Grade DMReactive diluent containing,Grade DSSilicone,Grade DWWater containing,andGrade DTThixotropic.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.NOTE1This specification resembles IEC 60455 in title only.Thecontent is significantly different.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:2D93 Test Methods for Flash Point by Pensky-MartensClosed Cup TesterD115 Test Methods for Testing Solvent Containing Var-nishes Used for Electrical InsulationD1711 Terminology Relating to Electrical InsulationD2519 Test Method for Bond Strength of Electrical Insulat-ing Varnishes by the Helical Coil TestD3056 Test Method for Gel Time of Solventless VarnishesD3145 Test Method for Thermal Endurance of ElectricalInsulating Varnishes by the Helical Coil MethodD3251 Test Method for Thermal Endurance Characteristicsof Electrical Insulating Varnishes Applied Over Film-Insulated Magnet WireD3278 Test Methods for Flash Point of Liquids by SmallScale Closed-Cup ApparatusD4733 Test Methods for Solventless Electrical InsulatingVarnishesD4880 Test Method for Salt Water Proofness of InsulatingVarnishes Over Enamelled Magnet WireD5637 Test Method for Moisture Resistance of ElectricalInsulating VarnishesD5638 Test Method for Chemical Resistance of ElectricalInsulating Varnishes2.2 Military Specifications:3MIL-PRF-17672 Hydraulic Fluid,Petroleum,InhibitedMIL-PRF-17331 Lubricating Oil,Synthetic Base P-D-680,Dry Cleaning SolventMIL-D-16791 Detergent,General Purpose,(Liquid,Non-Ionic)2.3 Other Standards:3NEMA MW1000 Magnet WireIEC 60455 Resin Based Reactive Compounds Used forElectrical Insulation3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this specification referto Terminology D1711.3.1.2 varnish,electrical insulating,na 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:solvent-containing and solventless.The solvent-containing varnish is a solution,dispersion,or emulsion of apolymer or mixture of polymers in a volatile,nonreactable1This specification 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 Aug.1,2020.Published September 2020.Originallyapproved in 1980.Last previous edition approved in 2013 as D3955 13.DOI:10.1520/D3955-20.2For 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.3Available from Global Engineering Documents,15 Inverness Way,EastEnglewood,CO 80112-5704,http:/.*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.liquid.The solventless type is a liquid resin system free ofvolatile,nonreactable solvents.4.Flexible or Rigid Classification4.1 This specification covers both flexible and rigid,solvent(including water)and solventless insulating varnishes.5.Thermal Classification5.1 The thermal classification of insulating varnishes cov-ered by this specification is determined by using Test MethodsD3145 and D3251 in conjunction with 18 AWG magnet wireconforming to MW 35-