1、Designation: D902 12Standard Test Methods forFlexible Resin-Coated Glass Fabrics and Glass Fabric TapesUsed for Electrical Insulation1This standard is issued under the fixed designation D902; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, 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. Scope*1.1 These test
3、 methods cover procedures for the testing ofresin-coated glass fabrics and glass fabric tapes (Note 1)tobeused as electrical insulation.NOTE 1Methods of testing varnished cloths and tapes are given inMethods D295.1.2 The warp threads in fabrics are the threads that areparallel with the length dimens
4、ion as manufactured.1.3 The procedures appear as follows:Procedure SectionASTM TestMethod ReferenceBreaking Strength 22 28 D828Conditioning 68 .Dielectric Breakdown Voltage and Di-electric Strength29 38 D149, D295Dissipation Factor and Relative Permit-tivity52 60 D150, E104,D5032Effect of Elevated T
5、emperature 39 45 D1830Resistance to Oil 46 51 D3487Sampling 35 .Thermal Endurance 68 D1830Thickness 16 21 D374Thread Count 1215 .Weight 911 .Weight Loss at Elevated Temperature 61 67 D54231.4 The values stated in inch-pound units are to be regardedas the standard. The values in parentheses are for i
6、nformationonly.1.5 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.
7、 Specific warningstatement are given in 35.1.1 and 58.1.2. Referenced Documents2.1 ASTM Standards:2D149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD150 Test Methods for AC Loss Characteristics and Permit-
8、tivity (Dielectric Constant) of Solid Electrical InsulationD295 Test Methods for Varnished Cotton Fabrics Used forElectrical InsulationD374 Test Methods for Thickness of Solid Electrical Insu-lation (Withdrawn 2013)3D828 Test Method for Tensile Properties of Paper andPaperboard Using Constant-Rate-o
9、f-ElongationApparatus(Withdrawn 2009)3D1711 Terminology Relating to Electrical InsulationD1830 Test Method for Thermal Endurance of FlexibleSheet Materials Used for Electrical Insulation by theCurved Electrode MethodD3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD5032 Prac
10、tice for Maintaining Constant Relative Humidityby Means of Aqueous Glycerin SolutionsD5423 Specification for Forced-Convection Laboratory Ov-ens for Evaluation of Electrical InsulationE104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions1These methods are under the ju
11、risdiction 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 April 1, 2012. Published April 2012. Originallyapproved in 1946. Last previous edition approve
12、d in 2006 as D902 06. DOI:10.1520/D0902-12.2For 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
13、 version of this historical standard is referenced onwww.astm.org.*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 States12.2 IEEE Standard:IEEE No. 1 General Principles for Tem
14、perature Limits in theRating of Electrical Equipment4SAMPLING3. Selecting Sample Rolls3.1 Sample shipments of resin-coated glass fabrics and glassfabric tapes as specified in 3.2 and 3.3. Select the rolls or padsin such a manner as to be representative of the shipment.3.2 FabricSelect one roll from
15、each ten rolls or fractionthereof in a shipment of full-width fabric.3.3 TapeThe producer and consumer shall agree upon thenumber of rolls selected. Unless otherwise specified, a mini-mum of three rolls per lot shall be selected. For samplingpurposes, a lot consists of identifiable materials of the
16、sametype manufactured in one production run and offered fordelivery at the same time.4. Selecting Samples4.1 Cut off and discard not less than two turns of fabric orsix turns of tape from each roll or pad selected for samplingbefore the samples are selected.4.2 From shipments such as sheets of fabri
17、c or strips of tape,take samples representative of the shipment in accordance with4.1.5. Selecting Test Specimens5.1 Prepare the test specimens from samples as selected inSection 4 and as provided for in the individual test methods.CONDITIONING6. Terminology6.1 Definitions of Terms Specific to This
18、Standard:6.1.1 conditioning (of resin-coated glass fabrics or glassfabric tapes),nthe process of exposing test specimens of thematerial to a specified temperature, or to an atmosphere ofspecified relative humidity and temperature, for a specifiedperiod of time.7. Significance and Use7.1 The electric
19、al properties of resin-coated glass fabrics areaffected by their temperature and moisture content. For thisreason it is necessary to control these properties for a specifiedtime immediately prior to testing in order to attain reasonablygood reproducibility of test values. The time of exposure to the
20、conditioning atmosphere must be long enough to permit thetest specimen to reach a relatively stable value. Usually themoisture content of these materials has little effect on themechanical properties.8. Conditioning8.1 Unless otherwise specified in the individual testmethods, condition test specimen
21、s as described in 8.1.1, 8.1.2,or 8.1.3. In matters of dispute, consider 8.1.2 the refereemethod. Use the method described in 8.1.3 only if specificallyagreed upon by the producer and consumer.8.1.1 Condition the test specimen for 48 h in the StandardLaboratory Atmosphere (50 6 2 % relative humidity
22、 at atemperature of 23 6 1C (73.4 6 1.8F), and conduct the testsin the Standard Laboratory Atmosphere.8.1.2 Condition the test specimen for 48 h in the StandardLaboratory Atmosphere (50 6 2 % relative humidity at atemperature of 23 6 1C (73.4 6 1.8F), and conduct the testsimmediately upon removal of
23、 the test specimen from theconditioning room or chamber.8.1.3 Do not condition the test specimens if it is desired totest the material in the condition as received by the purchaser,but allow the packages containing the rolls of cloth or tapefrom which the specimens are to be taken to reach approxi-m
24、ately test-room temperature before the packages are openedand the specimens cut. Remove the specimens to be testedfrom the roll as required and test immediately, unless otherwisespecified.WEIGHT9. Terminology9.1 Definitions of Terms Specific to This Standard:9.1.1 weight (of resin-coated glass cloth
25、 and glass clothtapes),nthe weight per unit area as determined in accordancewith this method. It is usually expressed in pounds per squareyard for a specified nominal thickness.10. Significance and Use10.1 The ratio of resin weight to glass cloth weight, withinand between shipments, can be determine
26、d from the weight ofresin-coated glass cloth and glass cloth tape and the weight ofthe cloth base. This ratio is a factor in determining the electricalcharacteristics of the material. Weight values are useful forestimating weight in designing electrical equipment containinga constituent part of resi
27、n-coated cloth or tape.11. Procedure11.1 Determine the weight per unit area using the methodgiven in Test Methods D295.THREAD COUNT12. Terminology12.1 Definitions of Terms Specific to This Standard:12.1.1 thread count, nThe thread count of resin-coatedglass cloth refers to the count of the number of
28、 threads presentin the base glass cloth per linear inch (centimetre) of length orwidth, respectively.13. Significance and Use13.1 Thread count, together with the weight and the widthof the glass cloth, is accepted as the common means fordesignating and identifying cloth constructions.13.2 Certain of
29、 the physical and electrical properties ofwoven fabrics are dependent on thread count. That is, assuming4Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331, http:/www.ieee.org.D902 122the same size of yarn, an increase
30、 in thread count increases theweight, breaking strength, and density of the cloth. Also, thedielectric strength and power factor of the resin-coated fabricmay be changed by altering the number of threads per inch ofthe cloth.14. Procedure14.1 Determine the thread count in threads per inch or percent
31、imetre separately on both the warp and filling.15. Report15.1 The results of the warp or filling count shall bereported as threads per inch (centimetre).NOTE 2Before counting black resin-coated materials, it will benecessary to remove the resin film with a knife blade or other suitableinstrument. As
32、 an alternative method, liquid resin removers may be usedfor this purpose, provided specimens are dried before the thread count istaken.THICKNESS16. Terminology16.1 Definitions:16.1.1 thickness (of an electrical insulating material),ntheperpendicular distance between the two surfaces of interest,det
33、ermined in accordance with a standard method.17. Significance and Use17.1 This test is of value in determining whether thematerial meets specified tolerances for thickness. In addition,thickness values are essential because of the importance ofspace factor in designing electrical equipment.17.2 Dete
34、rmination of dielectric strength, usually expressedin volts per mil, also necessitates thickness measurements.18. Test Specimens18.1 In the case of fabrics, cut a specimen 1 in. (25.4 mm)wide across the entire width.18.2 In the case of tapes, remove the specimens fromsamples selected in accordance w
35、ith Section 3. Prepare speci-mens 36 in. (914 mm) long.19. Procedure19.1 Unless otherwise specified, measure the thickness inaccordance with Method C of Test Methods D374 with thefollowing modifications:19.1.1 In making thickness measurements, use only onelayer of the material.19.1.2 In the case of
36、fabrics, take ten measurements equallyspaced across the width of the specimen. The thickness of thecloth is the average of the ten measurements.19.1.3 In the case of tapes, unless otherwise specified, taketen measurements equally spaced along the length of eachspecimen. The thickness of the tape is
37、the average of the tenmeasurements.19.1.4 The diameter of the pressure foot is 0.250 6 0.001in. (6.35 6 0.03 mm) and the diameter of the anvil is at least2 in. (50 mm). The pressure on the pressure foot (dead weight)is 25 6 2 psi or 172 6 14 kPa.19.1.5 Methods A and C of Test Methods D374 shall not
38、beconsidered interchangeable.19.2 Method B of Test Methods D374 may be used uponspecific agreement between the producer and consumer.20. Report20.1 Report the average, maximum, and minimumthicknesses, in inches, reported to the nearest 0.0001 in.(0.0025 mm).21. Precision and Bias21.1 This test metho
39、d has been in use for many years, but noinformation has been presented to ASTM upon which to basea statement of precision. No activity has been planned todevelop such information.21.2 This test method has no bias because the value forthickness is determined solely in terms of this test methoditself.
40、BREAKING STRENGTH22. Terminology22.1 Definitions of Terms Specific to This Standard:22.1.1 breaking strength (of resin-coated glass cloths andglass cloth tapes),nthe force per unit width required to breakthe cloth or tapes when tested under certain prescribed condi-tions.23. Significance and Use23.1
41、 The breaking strength of finished cloth and tape is ofimportance as a measure of its ability to withstand reasonablepulling without failure while being applied in service.24. Apparatus24.1 Use a constant rate of elongation type tensile testingmachine as described in Test Method D828.25. Test Specim
42、ens25.1 From full-width fabric samples or from sample rolls oftapes over 1 in. (25.4 mm) in width cut specimens 1 in. inwidth (Note 3) and not less than 12 in. (305 mm) in length. Fortape having a nominal width of 1 in. or under, preparespecimens of the original width and not less than 12 in. inleng
43、th.NOTE 3In the case of specimens 1 in. in width and having ultimatebreaking loads above the capacity of the machine, it is permissible toreduce the width of the specimen to 0.5 in. (12.7 mm).25.2 In the case of fabrics, cut five specimens with the sidesparallel to the warp threads and five with the
44、 sides parallel tothe filling threads (Note 4), from samples selected in accor-dance with Section 4.NOTE 4Frequently the fill threads of glass fabrics used to manufactureresin-coated glass fabrics do not run in a straight line and are notperpendicular to the warp threads. Breaking strength from spec
45、imens cutperpendicular to the warp thread may, therefore, be highly variable.D902 12325.3 In the case of tapes, cut five specimens from each rollselected in accordance with 3.3.26. Procedure26.1 Maintain the clearance distance between jaws at 6 in.(153 mm).26.2 The rate of separation of the jaws mus
46、t be 12 6 0.5in/min (305 6 13 mm/min).26.3 Reject all readings obtained when the specimen breaksat or in the jaws.27. Report27.1 The breaking strength of a roll of fabric or tape is theaverage of the breaking strengths of all the specimens testedfrom the roll. Report the average, maximum, and minimu
47、mbreaking strengths in pounds per inch width (or newtons permetre), together with the width and nominal thickness.27.2 In the case of fabrics, report the breaking strengths ofthe warp threads and the filling threads separately.28. Precision and Bias28.1 This test method has been in use for many year
48、s, but noinformation has been presented to ASTM upon which to basea statement of precision. No activity has been planned todevelop such information.28.2 This test method has no bias because the value forbreaking strength is determined solely in terms of this testmethod itself.DIELECTRIC BREAKDOWN VO
49、LTAGE ANDDIELECTRIC STRENGTH29. Terminology29.1 Definitions:29.1.1 For definitions of dielectric breakdown voltage anddielectric strength refer to Terminology D1711.30. Significance and Use30.1 Dielectric strength of resin-coated glass fabric or tapeinsulating material is of significance for the following reasons:30.1.1 Insulating materials are subjected to electricalstresses in service for long periods of time. Although theseservice stresses are usually a small fraction of the breakdownstresses determined by dielectric strength tests, it has be
