ASTM D257.21915 绝缘材料电阻测试方法

ASTM标准

Designation: D 257– 99

An American National Standard

Standard Test Methods for

DC Resistance or Conductance of Insulating Materials1 This standard is issued under the xed designation D 257; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.

1. Scope 1.1 These test methods cover direct-current procedures for the determination of dc insulation resistance, volume resistance, volume resistivity, surface resistance, and surface resistivity of electrical insulating materials, or the corresponding conductances and conductivities. 1.2 These test methods are not suitable for use in measuring the electrical resistivity/conductivity of moderately conductive materials. Use Test Method D 4496 to evaluate such materials. 1.3 The test methods and procedures appear in the following sections: Test Method or Procedure Calculation Choice of Apparatus and Test Method Cleaning Solid Specimens Conditioning of Specimens Effective Area of Guarded Electrode Electrode Systems Factors Affecting Insulation Resistance or Conductance Measurements Humidity Control Liquid Specimens and Cells Precision and Bias Procedure for the Measurement of Resistance or Conductance Referenced Documents Report Sampling Signicance and Use Specimen Mounting Summary of Test Methods Terminology Test Specimens for Insulation, Volume, and Surface Resistance or Conductance Determination Typical Measurement Methods Section 13 7 10.1 11 X2 6 X1 11.2 9.4 15 12 2 14 8 5 10 4 3 9 X3

D 150 Test Methods for AC Loss Characteristics and Permittivity Dielectric Contant of Solid Electrical Insulation2 D 374 Test Methods for Thickness of Solid Electrical Insulation2 D 618 Practice for Conditioning Plastics for Testing3 D 1169 Test Method for Specic Resistance (Resistivity) of Electrical Insulating Liquids4 D 1711 Terminology Relating to Electrical Insulation2 D 4496 Test Method for DC Resistance or Conductance of Moderately Conductive Materials5 D 5032 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Glycerin Solutions5 E 104 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions6 3. Terminology 3.1 Denitions—The following denitions are taken from Terminology D 1711 and apply to the terms used in these test methods. 3.1.1 conductance, insulation, n—the ratio of the total volume and surface current between two electrodes (on or in a specimen) to the dc voltage applied to the two electrodes. 3.1.1.1 Discussion—Insulation conductance is the reciprocal of insulation resistance. 3.1.2 conductance, surface, n—the ratio of the current between two electrodes (on the surface of a specimen) to the dc voltage applied to the elect

rodes. 3.1.2.1 Discussion—(Some volume conductance is unavoidably included in the actual measurement.) Surface conductance is the reciprocal of surface resistance. 3.1.3 conductance, volume, n—the ratio of the current in the volume of a specimen between two electrodes (on or in the specimen) to the dc voltage applied to the two electrodes. 3.1.3.1 Discussion—Volume conductance is the reciprocal of volume resistance. 3.1.4 conductivity, surface, n—the surface conductance multiplied by that ratio of specimen surface dimensions (distance between electrodes divided by the width of electrodes dening the current path) which transforms the measured 2 3

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 a specic hazard statement, see 6.1.8. 2. Referenced Documents 2.1 ASTM Standards: 1 These test methods are under the jurisdiction of ASTM Committee D-9 on Electrical and Electronic Insulating Materials and are the direct responsibility of Subcommittee D09.12 on Electrical Tests. Current edition approved Oct. 10, 1999. Published November 1999. Originally published as D 257– 25 T. Last previous edition D 257– 93 (1998).

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