【国外标准】 Standard Test Methods for Varnished Cotton Fabrics Used for Electrical Insulation (Withdrawn 2020)

The thickness test is necessary to determine whether the material meets specified tolerances for thickness. In addition, thickness values are essential because of the importance of space factor in designing electrical equipment.1.1 These test methods cover procedures for the testing of varnished cotton fabrics and varnished cotton fabric tapes (Note 1) to be used as electrical insulation and are directly applicable to both “straight-cut” and “bias-cut” materials, unless otherwise stated in the test method.Note 1—Methods of testing varnished glass fabrics and tapes are given in Test Methods D902.1.2 The procedures appear in the following order:Procedures Sections ASTM Test MethodsBreaking Strength 20 to 27 ...ConditioningDielectric Breakdown Voltage 543 to 46 ...D149Dielectric Breakdown Voltage Under Elongation 47 to 53 D149Dissipation Factor and Permittivity 54 to 60 D150ElongationResistance to Oil 35 to 4268 to 73 ...D92Selection of Test Specimens 4 ...Tear Resistance 28 to 34 D689Thickness 6 to 10 D374Thread Count 15 to 19 ...Volume Resistance 61 to 67 D257Weight 11 to 14 ...1.3 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 44.4, 51.1, 58.1, and 65.1.Note 2—This standard resembles IEC 60394–2 in title only. The content is significantly different.^REFERENCE:ASTM Standards:D92 Test Method for Flash and Fire Points by Cleveland Open Cup TesterD149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power FrequenciesD150 Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical InsulationD257 Test Methods for DC Resistance or Conductance of Insulating MaterialsD374 Test Methods for Thickness of Solid Electrical InsulationD689 Test Method for Internal Tearing Resistance of Paper (Withdrawn)D902 Test Methods for Flexible Resin-Coated Glass Fabrics and Glass Fabric Tapes Used for Electrical InsulationD1711 Terminology Relating to Electrical InsulationIEC Standard:IEC 60394–2 Varnished Fabrics for Electrical Purposes Part 2: Methods of Test