ASTM_D_295_-_12.pdf

Designation:D29512Standard Test Methods forVarnished Cotton Fabrics Used for Electrical Insulation1This standard is issued under the fixed designation D295;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.Scope1.1 These test methods cover procedures for the testing ofvarnished cotton fabrics and varnished cotton fabric tapes(Note 1)to be used as electrical insulation and are directlyapplicable to both“straight-cut”and“bias-cut”materials,unless otherwise stated in the test method.NOTE1Methods of testing varnished glass fabrics and tapes are givenin Test Methods D902.1.2 The procedures appear in the following order:ProceduresSectionsASTM TestMethodsBreaking Strength20 to 27.ConditioningDielectric Breakdown Voltage543 to 46.D149Dielectric Breakdown Voltage Under Elongation47 to 53D149Dissipation Factor and Permittivity54 to 60D150ElongationResistance to Oil35 to 4268 to 73.D92Selection of Test Specimens4.Tear Resistance28 to 34D689Thickness6 to 10D374Thread Count15 to 19.Volume Resistance61 to 67D257Weight11 to 14.1.3 The values stated in inch-pound units are to be regardedas the standard.The metric equivalents of inch-pound unitsmay be approximate.1.4 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 specificprecautionary statements,see 44.4,51.1,58.1,and 65.1.NOTE2This standard resembles IEC 603942 in title only.Thecontent is significantly different.2.Referenced Documents2.1 ASTM Standards:2D92 Test Method for Flash and Fire Points by ClevelandOpen Cup TesterD149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD150 Test Methods for AC Loss Characteristics and Permit-tivity(Dielectric Constant)of Solid Electrical InsulationD257 Test Methods for DC Resistance or Conductance ofInsulating MaterialsD374 Test Methods for Thickness of Solid Electrical Insu-lation(Withdrawn 2013)3D689 Test Method for Internal Tearing Resistance of Paper(Withdrawn 2009)3D902 Test Methods for Flexible Resin-Coated Glass Fabricsand Glass Fabric Tapes Used for Electrical InsulationD1711 Terminology Relating to Electrical Insulation2.2IEC Standard:IEC 603942 Varnished Fabrics for Electrical Purposes Part 2:Methods of Test43.Terminology3.1 DefinitionsFor definitions of terms used in these testmethods refer to Terminology D1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 weightof varnished cloth and varnished cloth tapes,the weight per unit area as determined in accordance with thistest method.It is usually expressed in pound per square yardfor a specified nominal thickness.3.2.2 threads per inchof varnished cloths,the count of thenumber of warp and filling yarns present in the base cloth perlinear inch of width or length,respectively.1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct responsibility ofSubcommittee D09.07 on Flexible and Rigid Insulating Materials.Current edition approved Jan.15,2012.Published February 2012.Originallyapproved in 1928.Last previous edition approved in 1994 as D295 94 which waswithdrawn in October 2009 and reinstated in January 2012.DOI:10.1520/D0295-12.2For 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,11 W 42nd St.,NewYork,NY 10036.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3 elongationthe amount of strain observed in a givenlength of varnished cloth or tape when subjected to prescribedloading conditions at prescribed atmospheric conditions.It isexpressed as a percentage of the initial length.3.2.4 oil resistanceof varnished cloth or tape,the abilityof the varnish film to withstand the attack of oil withoutexcessive impairment of its physical and electrical character-istics when the varnished cloth or tape is immersed in aspecified oil for a prescribed period of time at a giventemperature.4.Selection of Test Specimens4.1 Select specimens for test from portions of material freefrom defects.4.2 In the case of rolls of material other than those packedin oil,remove the outer two layers of