29.035.01 (Insulating materials in general) 标准查询与下载

ASTM D257-14 绝缘材料直流电阻或电导的标准试验方法

5.1 Insulating materials are used to isolate components of an electrical system from each other and from ground, as well as to provide mechanical support for the components. For this purpose, it is generally desirable to have the insulation resistance as high as possible, consistent with acceptable mechanical, chemical, and heat-resisting properties. Since insulation resistance or conductance combines both volume and surface resistance or conductance, its measured value is most useful when the test specimen and electrodes have the same form as is required in actual use. Surface resistance or conductance changes rapidly with humidity, while volume resistance or conductance changes slowly with the total change being greater in some cases. 5.2 Resistivity or conductivity is used to predict, indirectly, the low-frequency dielectric breakdown and dissipation factor properties of some materials. Resistivity or conductivity is often used as an indirect measure of: moisture content, degree of cure, mechanical continuity, or deterioration of various types. The usefulness of these indirect measurements is dependent on the degree of correlation established by supporting theoretical or experimental investigations. A decrease of surface resistance results either in an increase of the dielectric breakdown voltage because the electric field intensity is reduced, or a decrease of the dielectric breakdown voltage because the area under stress is increased. 5.3 All the dielectric resistances or conductances depend on the length of time of electrification and on the value of applied voltage (in addition to the usual environmental variables). These must be known and reported to make the measured value of resistance or conductance meaningful. Within the electrical insulation materials industry, the adjective “apparent” is generally applied to resistivity values obtained under conditions of arbitrarily selected electrification time. See X1.4. 5.4 Volume resistivity or conductivity is calculated from resistance and dimensional data for use as an aid in designing an insulator for a specific application. Studies have shown changes of resistivity or conductivity with temperature and humidity (1, 2, 3, 4).4 These changes must be known when designing for operating conditions. Volume resistivity or conductivity determinations are often used in checking the uniformity of an insulating material, either with regard to processing or to detect conductive impurities that affect the quality of the material and that are not readily detectable by other methods. 5.5 Volume resistivities above 1021 Ω·cm (1019 Ω·m), calculated from data obtained on specimens tested under usual laboratory conditions, are of doubtful validity, considering the limitations of commonly used measuring equipment. 5.6 Surface resistance or conductance cannot be measured accurately, only approximated, because some degree of volume resistance or conductance is always involved in the measurement. The measured value is also affected by the surface contamination. Surface contamination, and its rate of accumulation, is affected by many factors including electrostatic charging and interfacial tension. These, in turn, affect the surface resistivity. Surface resistivity or conductivity is considered to be related to material properties when contamination is involved but is not a material property of electrical insulation material......

Standard Test Methods for DC Resistance or Conductance of Insulating Materials

ASTM D3755-14 在直流电压应力作用下固体电绝缘材料的介电击穿电压及介电强度的标准试验方法

5.1 This test method is intended for use as a control and acceptance test for direct-voltage applications. It can also be used in the partial evaluation of material for specific end uses and as a means for detecting changes in material due to specific deteriorating causes. 5.2 Experience indicates that the breakdown value obtained with direct voltage usually will be approximately 2 to 4 times the rms value of the 60-Hz alternating-voltage breakdown. 5.3 For a nonhomogeneous test specimen, the distribution of voltage stress within the specimen is determined by impedance (largely capacitive) with alternating voltage. With an increasing direct voltage, the voltage distribution will still be largely capacitive, although this depends partly on the rate of voltage increase. After steady application of direct voltage the voltage division across the test specimen is determined by resistance. The choice of direct or alternating voltage depends upon the purpose for which the breakdown test is to be used, and to some extent, on the intended application of the material. 5.4 A more complete discussion of the significance of dielectric breakdown tests is given in Appendix X1 of this method and in Appendix X1 of Test Method D149. Those appendix sections of Test Method D149 that refer to alternating voltage are not applicable to the direct-voltage method. 1.1 This test method covers the determination of dielectric breakdown voltage and dielectric strength of solid electrical insulating materials under direct-voltage stress. 1.2 Since some materials require special treatment, reference shall also be made to ASTM specifications or to the test method directly applicable to the material to be tested. See Test Method D149 for the determination of dielectric strength of electrical insulating materials at commercial power frequencies. 1.3 This test method is similar to IEC Publication 243-2. All procedures in this test method are included in IEC 243-2. Differences between this test method and IEC 243-2 are largely editorial. 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. Specific precaution statements are given in Section 7.

Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials Under Direct-Voltage Stress

ASTM D495-14 固体电绝缘材料耐高压低电流干电弧性能的标准试验方法

4.1 The high-voltage, low-current type of arc resistance test is intended to simulate only approximately such service conditions as exist in alternating current circuits operating at high voltage, but at currents limited to units and tens of milliamperes. 4.2 In order to distinguish more easily among materials that have low arc resistance, the early stages of this test method are mild, and the later stages are successively more severe. The arc occurs intermittently between two electrodes resting on the surface of the specimen, in normal or inverted orientation. The severity is increased in the early stages by successively decreasing to zero the interval between flashes of uniform duration, and in later stages by increasing the current. 4.3 Four general types of failure have been observed: 4.3.1 Many inorganic dielectrics become incandescent, whereupon they are capable of conducting the current. Upon cooling, however, they return to their earlier insulating condition. 4.3.2 Some organic compounds burst into flame without the formation of a visible conducting path in the substance. 4.3.3 Others are seen to fail by “tracking,” that is, a thin wiry line is formed between the electrodes. 4.3.4 The fourth type occurs by carbonization of the surface until sufficient carbon is present to carry the current. 4.4 Materials often fail within the first few seconds after a change in the severity stage. When comparing the arc resistance of materials, much more weight shall be given to a few seconds that overlap two stages than to the same elapsed time within a stage. Thus, there is a much greater difference in arc resistance between 178 and 182 s than between 174 and 178 s.Note 3—Some investigators have reported attempts to characterize the remaining insulating value of the damaged area after failure by allowing the specimen to cool to room temperature, without disturbance of the original position of the electrodes, and then either (1) measuring the insulation resistance between the electrodes or (2) determining the percentage of breakdown voltage remaining relative to that obtained on an undamaged area of the specimen. A recommended circuit arrangement and test procedure for carrying out the second of these two means of characterizing the remaining insulating value of the damaged area is described in Appendix X1. Still another, and obvious, method of reevaluating the damaged area after failure is to repeat the arc resistance test after the specimen has cooled, with the electrodes undisturbed from their original positions. However, keep in mind that none of these methods will be universally applicable because of the severe physical damage to the test area in many instances. 1.1 This test method covers, in a preliminary fashion, the differentiation of similar materials’ resistance to the action of a high-voltage, low-current arc close to the surface of insulation, when a conducting path is formed causing the material to become conducting due to the localized thermal and chemical decomposition and erosion. 1.2 The usefulness of this test method is very severely limited by many restrictions and qualifications, some of which are described in the following parag......

Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation

ASTM F478-14 使用绝缘线路软管及保护套时保养的标准规范

1.1 This specification covers the in-service care, inspection, testing, and use voltage of insulating line hose and covers for protection of workers from accidental contact with energized electrical wires or equipment. 1.2 The following safety hazards caveat applies only to the test method portion, Section 7, of this specification: This standard does not purport to address all of the safety problems, 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. Specific precautionary statements are given in 7.2.1.

Standard Specification for In-Service Care of Insulating Line Hose and Covers

ASTM D4566-14 远程通信电线和电缆用绝缘体和套管的电气性能特性的标准试验方法

5.1 Electrical tests, properly interpreted, provide information with regard to the electrical properties of the insulation. The electrical test values give an indication as to how the insulation will perform under conditions similar to those observed in the tests. Electrical tests provide data for research and development, engineering design, quality control, and acceptance or rejection under specifications. 1.1 These test methods cover procedures for electrical testing of thermoplastic insulations and jackets used on telecommunications wire and cable and for the testing of electrical characteristics of completed products. To determine the procedure to be used on the particular insulation or jacket compound, or on the end product, reference should be made to the specification for the product. 1.2 The test methods appear in the following sections of this standard: Test Method Sections Electrical Tests of Insulation—In-Process 4 – 8 8199;DC proof test 8 8199;Insulation defect or fault rate 7 8199;Spark test 6 Electrical Tests of Completed Wire and Cable 9 –

Standard Test Methods for Electrical Performance Properties of Insulations and Jackets for Telecommunications Wire and Cable

ASTM D374M-13 固体电绝缘材料厚度的标准试验方法(公制)

5.1 Some electrical properties, such as dielectric strength, vary with the thickness of the material. Determination of certain properties, such as relative permittivity (dielectric constant) and volume resistivity, usually require a knowledge of the thickness. Design and construction of electrical machinery require that the thickness of insulation be known. 1.1 These test methods cover the determination of the thickness of several types of solid electrical insulating materials employing recommended techniques. Use these test methods except as otherwise required by a material specification. 1.2 The values stated in SI units are the standard. 1.3 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.

Standard Test Methods for Thickness of Solid Electrical Insulation (Metric)

ASTM D229-13 电绝缘用硬质薄板及板材的标准试验方法

18.1 This test method provides useful engineering information for evaluating the mechanical behavior of rigid electrical insulation at elevated temperature. When the proper exposure and test temperatures are chosen, depending on the material and end-use operating temperature, use the test method as one means of indicating relative thermal degradation of rigid insulating materials. 1.1 These test methods cover procedures for testing rigid electrical insulation normally manufactured in flat sheet or plate form. They are generally used as terminal boards, spacers, voltage barriers, and circuit boards. 1.2 Use Test Methods D619 (withdrawn) or Specification D710 for tests applying to vulcanized fibre. 1.3 Some of the test methods contained in this standard are similar to those contained in IEC 60893-2, which applies to rigid industrial laminated sheets based on thermosetting resins for electrical purposes. 1.4 The test methods appear in the following sections: Test Sections ASTM  Test Method Acetone extractable matter 83 to 84 D494 Arc resistance 47 D495 Ash 56 to 60 ... Bonding strength 49 to 54 ... Burning rate and flame resistance 61 to 75 ... Compressive strength 25 D695

Standard Test Methods for Rigid Sheet and Plate Materials Used for Electrical Insulation

ASTM D3636-13a 固体电绝缘材料的取样及质量评定的标准操作规程

1.1 This practice covers procedures for obtaining data pertaining to the quality of a lot of electrical insulating material and for making a judgement whether the lot meets the requirements of a material specification. 1.2 This practice is not intended to define a producer's internal quality control procedures but is designed to determine the acceptability of all, or some portion, of a quantity of electrical insulating material that is available for inspection by the user of the material. 1.3 This practice is intended to be used in conjunction with an existing material specification that specifies property characteristic limits, acceptable quality level (AQL), standard test methods, and specific sampling instructions. 1.4 In the absence of a specification as described in 1.3, use this practice as a guide, after establishment of agreed-upon property characteristics, limits, AQL, standard test methods, and specific sampling instructions. 1.5 It is intended that this be a practice for inspection by attributes. 1.6 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.

Standard Practice for Sampling and Judging Quality of Solid Electrical Insulating Materials

ASTM D3636-13ae1 固体电绝缘材料取样及质量评定的标准操作规程

1.1 This practice covers procedures for obtaining data pertaining to the quality of a lot of electrical insulating material and for making a judgement whether the lot meets the requirements of a material specification. 1.2 This practice is not intended to define a producer's internal quality control procedures but is designed to determine the acceptability of all, or some portion, of a quantity of electrical insulating material that is available for inspection by the user of the material. 1.3 This practice is intended to be used in conjunction with an existing material specification that specifies property characteristic limits, acceptable quality level (AQL), standard test methods, and specific sampling instructions. 1.4 In the absence of a specification as described in 1.3, use this practice as a guide, after establishment of agreed-upon property characteristics, limits, AQL, standard test methods, and specific sampling instructions. 1.5 It is intended that this be a practice for inspection by attributes. 1.6 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.

Standard Practice for Sampling and Judging Quality of Solid Electrical Insulating Materials

ASTM D2303-13 绝缘材料液态污染、斜面漏电痕迹和腐蚀的标准试验方法

4.1 These test methods differentiate among solid electrical insulating materials on the basis of their resistance to the action of voltage stresses along the surface of the solid when wet with an ionizable, electrically conductive liquid contaminant. 4.2 These test methods quantitatively evaluate, in a relative manner, the effects upon an insulating material resulting from the action of electrical discharges upon a material surface. The effects are similar to those that may occur in service under the influence of dirt combined with moisture condensed from the atmosphere. 4.2.1 In the field, the conditions resulting in electrical discharges occur sporadically. Degradation, often in the form of a conducting “track,” develops very slowly until it ultimately bridges the space between conductors thus causing complete electrical breakdown. 4.2.2 In these test methods, the conducting liquid contaminant is continuously supplied at an optimum rate to the surface of a test specimen in such a fashion that essentially continuous electrical discharge can be maintained. 4.2.3 By producing continuous surface discharge with controlled energy it is possible, within a few hours, to cause specimen failure which is similar to failure occurring under long-time exposure to the erratic conditions of service in the field. 4.2.4 The test conditions, which are standardized and accelerated, do not reproduce all of the conditions encountered in service. Use caution when making either direct or comparative service behavior inferences derived from the results of tracking tests. 4.3 The time-to-track a 1-in. (25-mm) distance at a specified voltage between electrodes separated 2 in. (50 mm) has also been found useful in categorizing insulating materials for indoor and protected outdoor applications, such as metal-clad switchgear. 4.4 The initial tracking voltage has been found useful for evaluating insulating materials to be used at high voltages or outdoors and unprotected, as well as for establishing (see 10.1) the test voltage for the time-to-track test. 4.5 In service many types of contamination cause tracking and erosion of different materials to different degrees. This method recognizes the importance of such variability and suggests the use of special test solutions to meet specific service needs. For example, an ionic contaminant containing, in addition, a carbonaceous component such as sugar is substituted to cause tracking on very resistant materials like polymethylmethacrylate. Such contamination is considered representative of some severe industrial environments. In this case, the time-to-track technique is used, since time is required to decompose the contaminant solution and build up conducting residues on the sample surface. 4.6 Very track-resistant materials, such as polymethylmethacrylate, typically erodes rather than track under more usual contaminant conditions in service. The use of this method for measuring erosion is consequently important. For erosion studies, only tests as a function of time at constant voltage are usefu......

Standard Test Methods for Liquid-Contaminant, Inclined-Plane Tracking and Erosion of Insulating Materials

ASTM D3636-13 固体电绝缘材料的取样及质量评定的标准实施规程

1.1 This practice covers procedures for obtaining data pertaining to the quality of a lot of electrical insulating material and for making a judgement whether the lot meets the requirements of a material specification. 1.2 This practice is not intended to define a producer's internal quality control procedures but is designed to determine the acceptability of all, or some portion, of a quantity of electrical insulating material that is available for inspection by the user of the material. 1.3 This practice is intended to be used in conjunction with an existing material specification that specifies property characteristic limits, acceptable quality level (AQL), standard test methods, and specific sampling instructions. 1.4 In the absence of a specification as described in 1.3, use this practice as a guide, after establishment of agreed-upon property characteristics, limits, AQL, standard test methods, and specific sampling instructions. 1.5 It is intended that this be a practice for inspection by attributes. 1.6 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.

Standard Practice for Sampling and Judging Quality of Solid Electrical Insulating Materials

ASTM D2520-13 在微波频率和1650℃时固体电绝缘材料复合介电常数的标准试验方法

4.1 Design calculations for such components as transmission lines, antennas, radomes, resonators, phase shifters, etc., require knowledge of values of complex permittivity at operating frequencies. The related microwave measurements substitute distributed field techniques for low-frequency lumped-circuit impedance techniques. 4.2 Further information on the significance of permittivity is contained in Test Methods D150. 4.3 These test methods are useful for specification acceptance, service evaluation, manufacturing control, and research and development of ceramics, glasses, and organic dielectric materials. 1.1 These test methods cover the determination of relative (Note 1) complex permittivity (dielectric constant and dissipation factor) of nonmagnetic solid dielectric materials. Note 1—The word “relative” is often omitted. 1.1.1 Test Method A is for specimens precisely formed to the inside dimension of a waveguide. 1.1.2 Test Method B is for specimens of specified geometry that occupy a very small portion of the space inside a resonant cavity. 1.1.3 Test Method C uses a resonant cavity with fewer restrictions on specimen size, geometry, and placement than Test Methods A and B. 1.2 Although these methods are used over the microwave frequency spectrum from around 0.5 to 50.0 GHz, each octave increase usually requires a different generator and a smaller test waveguide or resonant cavity. 1.3 Tests at elevated temperatures are made using special high-temperature waveguide and resonant cavities. 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.

Standard Test Methods for Complex Permittivity (Dielectric Constant) of Solid Electrical Insulating Materials at Microwave Frequencies and Temperatures to 1650^oC

ASTM D470-13 电线和电缆用交联绝缘材料与套管的标准试验方法

5.1 Physical tests, properly interpreted, provide information with regard to the physical properties of the insulation or jacket. The physical test values give an approximation of how the insulation will physically perform in its service life. Physical tests provide useful data for research and development, engineering design, quality control, and acceptance or rejection under specifications. 1.1 These test methods cover procedures for testing crosslinked insulations and jackets for wire and cable. To determine the test to be made on the particular insulation or jacket, refer to the product specification for that type. These test methods do not apply to the class of products known as flexible cords. 1.2 In many instances the insulation or jacket cannot be tested unless it has been formed around a conductor or cable. Therefore, tests are done on insulated or jacketed wire or cable in these test methods solely to determine the relevant property of the insulation or jacket and not to test the conductor or completed cable. 1.3 The procedures appear in the following sections:   Sections AC and DC Voltage Withstand Tests 22 to 29 Capacitance and Dissipation Factor Tests 38 to 44 Cold Bend 128 Cold Bend, Long-Time Voltage Test on Short Specimens 51 to 57 Double AC Voltage Test on Short Specimens 45 to 50 Electrical Tests of Insulation 17 to

Standard Test Methods for Crosslinked Insulations and Jackets for Wire and Cable

ASTM D5374-13 电气绝缘评估用实验室强制对流炉的标准试验方法

4.1 Ovens used for thermal evaluation of insulating materials are to be capable of maintaining uniform conditions of temperature and air circulation over the extended periods of time that are required for conducting these tests. Specification D5423 specifies the permissible deviations from absolute uniformity that have been generally accepted internationally for these ovens. These test methods include procedures for measuring these deviations and other specified characteristics of the ovens. 1.1 These test methods cover procedures for evaluating the characteristics of forced-convection ventilated electrically-heated ovens, operating over all or part of the temperature range from 20°C above the ambient temperature to 500°C and used for thermal endurance evaluation of electrical insulating materials. 1.2 These test methods are based on IEC Publication 216-4-1, and are technically identical to it. This compilation of test methods and an associated specification, D5423, have replaced Specification D2436. 1.3 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.

Standard Test Methods for Forced-Convection Laboratory Ovens for Evaluation of Electrical Insulation

ASTM D3638-12 绝缘材料比较漏电痕迹指数标准试验方法

Electrical equipment can fail as a result of electrical tracking of insulating material that is exposed to various contaminating environments and surface conditions. There are a number of ASTM and other tests designed to quantify behavior of materials, especially at relatively high voltages. This method is an accelerated test which at relatively low test voltages, provides a comparison of the performance of insulating materials under wet and contaminated conditions. The comparative tracking index is not related directly to the suitable operating voltage in service. When organic electrical insulating materials are subjected to conduction currents between electrodes on their surfaces, many minute tree-like carbonaceous paths or tracks are developed near the electrodes. These tracks are oriented randomly, but generally propagate between the electrodes under the influence of the applied potential difference. Eventually a series of tracks spans the electrode gap, and failure occurs by shorting of the electrodes. The conditions specified herein are intended, as in other tracking test methods, to produce a condition conducive to the formation of surface discharges and possible subsequent tracking. Test conditions are chosen to reproducibly and conveniently accelerate a process; for this reason, they rarely reproduce the varied conditions found in actual service. Therefore, while tracking tests serve to differentiate materials under given conditions, results of tracking tests cannot be used to infer either direct or comparative service behavior of an application design. Rather, tracking test results provide a tool for judging the suitability of materials for a given application. The suitability can only be verified through testing the design in actual end use or under conditions which simulate end use as closely as possible.1.1 This test method evaluates in a short period of time the low-voltage (up to 600 V) track resistance or comparative tracking index (CTI) of materials in the presence of aqueous contaminants. 1.2 The values stated in metric (SI) units are to be regarded as standard. The inch-pound equivalents of the metric units are approximate. 1.3 This standard is technically equivalent to the version of IEC Publication 112 cited in 2.2. However, the 2007 version of IEC 60112 Fourth Edition yields numerical CTI values that are very likely to differ significantly from this standard. 1.4 This standard does not purport to address all of the safety problems, 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.

Standard Test Method for Comparative Tracking Index of Electrical Insulating Materials

ASTM D668-12 电绝缘用硬条和硬管尺寸规格测量的标准试验方法

1.1 These test methods cover the measurement of the dimensions of all rigid rods and tubes used as electrical insulation, the limitations imposed being those of the size range of the more common forms of measuring instruments used. 1.2 Where the number of tests to be made or the specifications covering the rod or tube justify its use, it is acceptable to use an accurately calibrated ???go-and-no-go??? ring gage of suitable size. 1.3 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.

Standard Test Methods of Measuring Dimensions of Rigid Rods and Tubes Used for Electrical Insulation

ASTM D3850-12 用热解重量法测定固体电绝缘材料快速热降解的标准试验方法

Thermogravimetry is useful in determining the dynamic functional effect of temperature on the amount of volatile materials leaving a specimen as the latter is heated progressively to higher temperatures. TGA can be useful for process control, process development, material evaluation, and for identification and quality control in specifications. The thermal stability of a material can be associated with the degree and time rate of mass loss as a function of temperature. TGA curves can, therefore, be used as a preliminary screen method in the evaluation of relative behavior of insulating materials of the same generic family. The functional temperature-life relationship of an insulating material in any given application depends on a number of service and environmental factors. Therefore, the information obtained from TGA curves is not adequate by itself to describe the thermal capability of an insulating material. Refer to the Appendix for further discussion of the interpretation of TGA data.1.1 This test method outlines a procedure for obtaining thermogravimetric (TGA) data on solid polymeric materials intended for use as electrical insulating materials. 1.2 Do not use this standard to quantify an estimate of the long-term thermal capability for any electrical insulating material. If a relationship exists between TGA and the long-term thermal capabilities of a material, then that fact must be established and made public, preferably by comparing data between a candidate and another material known to display similar failure modes. 1.3 The values stated in SI units are the standard. 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.

Standard Test Method for Rapid Thermal Degradation of Solid Electrical Insulating Materials By Thermogravimetric Method (TGA)

ASTM D5470-12 热导性电绝缘材料的热传输特性的标准试验方法

This standard measures the steady state thermal impedance of electrical insulating materials used to enhance heat transfer in electrical and electronic applications. This standard is especially useful for measuring thermal transmission properties of specimens that are either too thin or have insufficient mechanical stability to allow placement of temperature sensors in the specimen as in Test Method E1225. This standard imposes an idealized heat flow pattern and specifies an average specimen test temperature. The thermal impedances thus measured cannot be directly applied to most practical applications where these required uniform, parallel heat conduction conditions do not exist. This standard is useful for measuring the thermal impedance of the following material types. Type I8212;Viscous liquids that exhibit unlimited deformation when a stress is applied. These include liquid compounds such as greases, pastes, and phase change materials. These materials exhibit no evidence of elastic behavior or the tendency to return to initial shape after deflection stresses are removed. Type II8212;Viscoelastic solids where stresses of deformation are ultimately balanced by internal material stresses thus limiting further deformation. Examples include gels, soft, and hard rubbers. These materials exhibit linear elastic properties with significant deflection relative to material thickness. Type III8212;Elastic solids which exhibit negligible deflection. Examples include ceramics, metals, and some types of plastics. The apparent thermal conductivity of a specimen can be calculated from the measured thermal impedance and measured specimen thickness if the interfacial thermal resistance is insignificantly small (nominally less than 1 %) compared to the thermal resistance of the specimen. The apparent thermal conductivity of a sample material can be accurately determined by excluding the interfacial thermal resistance. This is accomplished by measuring the thermal impedance of different thicknesses of the material under test and plotting thermal impedance versus thickness. The inverse of the slope of the resulting straight line is the apparent thermal conductivity. The intercept at zero thickness is the sum of the contact resistances at the two surfaces. The contact resistance can be reduced by applying thermal grease or oil to the test surfaces of rigid test specimens (Type III).1.1 This standard covers a test method for measurement of thermal impedance and calculation of an apparent thermal conductivity for thermally conductive electrical insulation materials ranging from liquid compounds to hard solid materials. 1.2 The term “thermal conductivity” applies only to homogeneous materials. Thermally conductive electrical insulating materials are usually heterogeneous and to avoid confusion this test method uses “apparent thermal conductivity” for determining thermal transmission properties of both homogeneous and heterogeneous materials. 1.3 The values stated in SI units are to be regarded as standard. 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.

Standard Test Method for Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials

ASTM D3874-12 用电热丝法测量材料着火性的标准试验方法

During operation of electrical equipment, including wires, resistors, and other conductors, it is possible for overheating to occur, under certain conditions of operation, or when malfunctions occur. When this happens, a possible result is ignition of the insulation material. This test method assesses the relative resistance of electrical insulating materials to ignition by the effect of hot wire sources. This test method determines the average time, in seconds, required for material specimens to ignite under the specified conditions of test. This method is suitable to characterize materials, subject to the appropriate limitations of an expected precision of ±15 %, to categorize materials. In this procedure the specimens are subjected to one or more specific sets of laboratory conditions. If different test conditions are substituted or the end-use conditions are changed, it is not always possible by or from this test to predict changes in the fire-test-response characteristics measured. Therefore, the results are valid only for the fire test exposure conditions described in this procedure.1.1 This test method is intended to differentiate, in a preliminary fashion, among materials with respect to their resistance to ignition because of their proximity to electrically-heated wires and other heat sources. 1.2 This test method applies to molded or sheet materials available in thicknesses ranging from 0.25 to 6.4 mm (0.010 to 0.25 in.). 1.3 This test method applies to materials that are rigid at normal room temperatures. That is, it applies to materials for which the specimen does not deform during preparation, especially during the wire-wrapping step described in 10.1. Examples of deformation that render this test method inapplicable include: 1.3.1 Bowing, in either a transverse or a longitudinal direction, or twisting of the specimen, during the wire-wrapping step, to a degree visible to the eye. 1.3.2 Visible indentation of the wrapped wire into the specimen. 1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. (See for further details.) 1.5 This test method measures and describes the response or materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions. 1.6 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. 1.7 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these tests. Note 18212;Although this test method and IEC 60695-2-20, differ in approach and in detail, data obtained using either are technically equivalent.

Standard Test Method for Ignition of Materials by Hot Wire Sources

ASTM D2132-12 电绝缘材料的尘雾起痕和耐腐蚀性的标准试验方法

Method8212;It is possible that electrical insulation in service will fail as a result of tracking, erosion, or a combination of both, if exposed to high relative humidity and contamination environments. This is particularly true of organic insulations in outdoor applications where the surface of the insulation becomes contaminated by deposits of moisture and dirt, for example, coal dust or salt spray. This test method is an accelerated test that simulates extremely severe outdoor contamination. It is believed that the most severe conditions likely to be encountered in outdoor service in the United States will be relatively mild compared to the conditions specified in this test method. Test Results8212;Materials can be classified by this test method as tracking-resistant, tracking-affected, or tracking-susceptible. The exact test values for these categories as they apply to specific uses will be specified in the appropriate material specifications, but guideline figures are suggested in Note 4. Tracking-resistant materials, unless erosion failure occurs first, have the potential to last many hundreds of hours (Note 5). Erosion, though it is possible that it will progress laterally, generally results in a failure perpendicular to the specimen surface. Therefore, compare only specimens of the same nominal thickness for resistance to tracking-induced erosion. Estimate the extent of erosion from measurements of the depth of penetration of the erosion. Place materials that are not tracking-susceptible in three broad categorieserosion-resistant, erosion-affected, and erosion-susceptible. When the standard thickness specimen is tested, the following times to failure typify the categories (Note 6): Erosion-susceptible5 to 50 h Erosion-affected50 to 200 h Erosion-resistantover 200 h Note 48212;Tracking-susceptible materials usually fail within 5 h. Tracking-affected materials usually fail before about 100 h. Note 58212;This information is derived from the individual experiences of eight laboratories using this test method since its publication as a suggested test method in June 1957, and from the results of an organized test program among these laboratories. Note 68212;In a normal distribution approximately 68 % of all test values are included within ±1 standard deviation of the mean. Interpretation of Test Results8212;This test method provides information that allows classification as described in 6.2. The comparison of materials within the same group is likely to be ambiguous unless three or more replicate specimens are tested. When the test method is used for specification purposes, do not establish simple minimum values without consideration of the large variance to be expected in test results. It is recommended that quality levels and specification minima be determined by statistical techniques.1.1 This test method is intended to differentiate solid electrical insulating materials with respect to their resistance to the action of electric arcs produced by conduction through surface films of a specified contaminant containing moisture. Test Methods and

Standard Test Method for Dust-and-Fog Tracking and Erosion Resistance of Electrical Insulating Materials