1、Designation: D 1830 99 (Reapproved 2005)An American National StandardStandard Test Method forThermal Endurance of Flexible Sheet Materials Used forElectrical Insulation by the Curved Electrode Method1This standard is issued under the fixed designation D 1830; the number immediately following the des
2、ignation 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 (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use
3、by agencies of the Department of Defense.1. Scope1.1 This test method provides a procedure for evaluatingthermal endurance of flexible sheet materials by determiningdielectric breakdown voltage at room temperature after agingin air at selected elevated temperatures. Thermal endurance isexpressed in
4、terms of a temperature index.1.2 This test method is applicable to such solid electricalinsulating materials as coated fabrics, dielectric films, compos-ite laminates, and other materials where retention of flexibilityafter heat aging is of major importance (see Note 4).1.3 This test method is not i
5、ntended for the evaluation ofrigid laminate materials nor for the determination of thermalendurance of those materials which are not expected orrequired to retain flexibility in actual service.1.4 The values stated in acceptable metric units are to beregarded as the standard. The values in parenthes
6、es are forinformation only.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 p
7、rior to use. For a specifichazard statement, see 10.1.2. Referenced Documents2.1 ASTM Standards:2D 149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD 374 Test Methods for Thickness of Solid Electrical Insu-
8、lationD 5423 Specification for ForcedConvection LaboratoryOvens for Evaluation of Electrical Insulation.2.2 Institute of Electrical and Electronics Engineers Pub-lications:3IEEE No. 1 General Principles for Temperature Limits inthe Rating of Electrical EquipmentIEEE No. 101A Guide for the Statistica
9、l Analysis of Ther-mal Life Test Data (including Appendix A)2.3 IEC Publications:IEC 216 Guide for the Determination of Thermal EnduranceProperties of Electrical Insulating Materials (Parts 1 and2)43. Terminology3.1 Definitions:3.1.1 temperature index, na number which permits com-parison of the temp
10、erature/time characteristics of an electricalinsulating material, or a simple combination of materials, basedon the temperature in degrees Celsius which is obtained byextrapolating the Arrhenius plot of life versus temperature to aspecified time, usually 20 000 h.3.1.2 thermal life, nthe time necess
11、ary for a specificproperty of a material, or simple combination of materials, todegrade to a defined end point when aged at a specifictemperature.3.1.3 thermal life curve, na graphical representation ofthermal life at a specified aging temperature in which the valueof a property of a material, or a
12、simple combination ofmaterials, is measured at room temperature and the valuesplotted as a function of time.3.2 Definitions of Terms Specific to This Standard:3.2.1 thermal endurance grapha straight-line plot of thelogarithm of thermal life in hours versus the reciprocal of theabsolute aging tempera
13、ture in kelvins (also known as theArrhenius plot).1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.19 on Dielectric Sheet and Roll ProductsCurrent edition approved Sept. 1, 2005. Pub
14、lished October 2005. Originallyapproved in 1961. Last previous edition approved in 1999 as D 1830 99.2For 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 D
15、ocument Summary page onthe ASTM website.3Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM Int
16、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 Specimens are aged in air at a minimum of threetemperatures above the expected use temperature of the mate-rial. Dielectric breakdown voltage tests in air at room tempera-ture
17、 are periodically made to determine the time of aging ateach test temperature required to reduce the breakdown voltageto a value of 12 kV/mm (300 V/mil) of original thickness.These thermal life values are used to construct a thermalendurance graph by means of which temperature indices maybe estimate
18、d corresponding to a thermal life as specified in thematerial specification or as agreed upon between the user andthe supplier.NOTE 1This test method is not applicable to materials having aninitial dielectric breakdown voltage of less than 12 kV/mm (300 V/mil) oforiginal thickness unless lower endpo
19、int values are agreed upon orindicated in the applicable material specifications.5. Significance and Use5.1 Amajor factor affecting the life of insulating materials isthermal degradation. Other factors, such as moisture andvibration, may cause failures after the material has beenweakened by thermal
20、degradation.5.2 Electrical insulation is effective in electrical equipmentonly as long as it retains its physical and electrical integrity.Thermal degradation may be characterized by weight change,porosity, crazing, and generally a reduction in flexibility, and isusually accompanied by an ultimate r
21、eduction in dielectricbreakdown voltage.6. Apparatus6.1 Electrode Test FixtureThe fixture shall be in accor-dance with the dimensions shown in Fig. 1 and Fig. 2.Electrodes shall be of polished brass, with the upper electrodehaving a mass of 1.8 6 0.05 kg (4.0 6 0.1 lb).6.2 Dielectric Breakdown Test
22、SetThe set shall meet therequirements of Test Method D 149.6.3 OvensOvens shall meet the requirements of Specifi-cation D 5423 Type II.Insulation Thickness Dimension R Dimension H Dimension Dmm in. mm in. mm in. mm in.0.18 0.007 4.55 0.179 8.15 0.321 8.71 0.3440.25 0.010 6.48 0.255 6.22 0.245 2.45 0
23、.4900.30 0.012 7.77 0.306 4.93 0.194 4.94 0.588Tolerance for R and D = 60.03 mm (0.001 in.)Tolerance for H = 60.05 mm (0.002 in.)FIG. 1 Curved Electrode DetailsFIG. 2 Curved Electrode and HolderD 1830 99 (2005)26.4 MicrometerThe micrometer shall be of the dead-weight type specified in Methods C or D
24、 of Test MethodsD 374, having a pressor foot 6.35 6 0.03 mm (0.25 6 0.001in.) in diameter and an anvil of at least 50 mm (2 in.) indiameter and shall exert a pressure of 0.17 6 0.01 MPa (25 62 psi) on the anvil.7. Test Specimens7.1 Test specimens shall be at least 250 mm (9.84 in.) longby 130 mm (5.
25、12 in.) wide, with the machine direction parallelto the longer direction.7.2 A set of test specimens consists of five specimens.Prepare one set for initial (unaged) tests and five sets for eachaging temperature chosen (15 sets for three temperatures).7.3 In the case of coated glass fabrics, make tes
26、ts on0.18-mm (0.007-in.) material having 0.08-mm (0.003-in.) or0.10-mm (0.004-in.) base cloth, or on 0.25-mm (0.010-in.) or0.30-mm (0.012-in.) material having respectively 0.10-mm(0.004-in.) or 0.13-mm (0.005-in.) base cloth.NOTE 2Experience has shown that unrealistically extended life datausually r
27、esult when the base fabrics of glass exceed the thicknessesspecified previously for the corresponding coated thicknesses. Similardata are not available for other types of coated fabrics, and the user of thistest method is urged to investigate this relationship to determine similarlimitations, if any
28、.8. Test Specimen Selection8.1 Select test specimens from the sample in such mannerthat they are randomly distributed among the sets.NOTE 3This can be conveniently accomplished by the followingprocedure, as an example: In the case of full-width material in rolls orsheets, select an area sufficient t
29、o provide a panel about 1 m (3.28 ft) wideby 3 m (9.84 ft) long. Using a suitable marking device, construct a grid of7 lines spaced 130 mm (5.12 in.) across and 12 lines spaced 250 mm (9.84in.) down, with an edge margin of about 50 mm (1.97 in.) on each side.This will provide 84 boxes, each delineat
30、ing a test specimen. Number theboxes consecutively across and down the grid. Using a set of randomnumbers, obtain a selection of 16 sets of test specimens. In the case of slitmaterial in rolls, number specimens as removed from the roll and obtaina random selection of test sets as in 8.1.9. Selection
31、 of Test Temperatures9.1 Expose the material at not less than three temperatures.Any temperature that gives a thermal life of less than 100 h isconsidered too high to be used in this evaluation. Choose thelowest temperature such that (1) a thermal life of at least 5000h is obtained and (2) it shall
32、not be more than 25C higher thanthe estimated temperature index. Exposure temperatures shalldiffer by at least 20C.9.2 Select exposure temperatures in accordance with thoseshown in Table 1 as indicated by the anticipated temperatureindex of the material under test. It is recommended thatexploratory
33、tests be first made at the highest temperature toobtain data establishing the validity of the 100 h minimum liferequirement (see 9.1), and that this be used as a guide for theselection of the lower test temperatures.10. Procedure10.1 WARNINGLethal voltages are a potential hazardduring the performanc
34、e of this test. It is essential that the testapparatus, and all associated equipment electrically connectedto it, be properly designed and installed for safe operation.Solidly ground all electrically conductive parts which it ispossible for a person to contact during the test. Provide meansfor use a
35、t the completion of any test to ground any parts whichwere at high voltage during the test or have the potential foracquiring an induced charge during the test or retaining acharge even after disconnection of the voltage source. Thor-oughly instruct all operators as to the correct procedures forperf
36、orming tests safely. When making high voltage tests,particularly in compressed gas or in oil, it is possible for theenergy released at breakdown to be suffcient to result in fire,explosion, or rupture of the test chamber. Design test equip-ment, test chambers and test specimens so as to minimize the
37、possibility of such occurrences and to eliminate the possibilityof personal injury. If the potential for fire exists, have firesuppression equipment available.10.2 Thickness MeasurementMake 16 thickness measure-ments before aging, using one specimen from each set pre-pared. Determine the thickness i
38、n accordance with Methods Cor D of Test Methods D 374, holding the pressor foot on thespecimen for 2 s before taking a reading. Compute the averagethickness in millimetres or inches.10.3 Dielectric Breakdown Voltage (Unaged)Conditionone set of specimens for at least 48 h at 23 6 1C and 50 62 % relat
39、ive humidity. Determine the dielectric breakdownvoltage in air at room temperature by the short-time test of TestMethod D 149, using a rate of voltage rise of 500 V/s. Makeone measurement on each specimen and compute the averagedielectric breakdown voltage for the set.TABLE 1 Suggested Exposure Temp
40、eratures and Cycle DurationsACycleDuration,daysTemperatures Corresponding to the Estimated Temperature Index Range, CClass 105BClass 130 Class 155 Class 180 Class 200 100109 110119 120129 130139 140149 150159 160169 170179 180189 190199 200209 210219 220229 2302391 170 180 190 200 210 220 230 240 25
41、0 260 270 280 290 3002 160 170 180 190 200 210 220 230 240 250 260 270 280 2904 150 160 170 180 190 200 210 220 230 240 250 260 270 2807 140 150 160 170 180 190 200 210 220 230 240 250 260 27014 130 140 150 160 170 180 190 200 210 220 230 240 250 26028 120 130 140 150 160 170 180 190 200 210 220 230
42、 240 25049 110 120 130 140 150 160 170 180 190 200 210 220 230 240ATaken from IEC Publication 216-1.BClasses shown correspond to those described in IEEE 1. Materials representative of these classes include: 105-organic varnished cotton cloth, 130-organic varnishedglass cloth, 155-polyester coated gl
43、ass cloth, 180/200-silicone resin and rubber coated glass cloth.D 1830 99 (2005)310.4 Aging of SpecimensTag five sets of specimens byany reliably permanent means and expose the sets in the ovenat the highest temperature. Position the sets so that freemovement of air exists across both sides of the s
44、pecimens.NOTE 4For materials that tend to warp appreciably in heat, specimensmay be weighted (in cases where the oven is designed for vertical airmovement) or mounted on restraining frames. In either case, the methodof restraint shall allow for normal shrinkage during aging and not induceelongation
45、or stress in the specimens. In cases where the specimensbecome warped, the operator shall endeavor to select portions of thespecimens for dielectric breakdown voltage tests so that the electrodes donot prematurely damage the specimens by distortion.10.5 Testing of Specimens:10.5.1 Remove one set of
46、specimens after completion of thecycle shown in Table 1. Condition the set for4hat236 1Cand 50 6 2 % relative humidity.10.5.2 Immediately make one dielectric breakdown voltagemeasurement in air at room temperature on each specimen ofthe set and compute the average breakdown voltage. Return theset to
47、 the aging oven.10.5.3 Remove the same set at the end of the next agingperiod, condition as prescribed in 10.5.1 and again measure thebreakdown voltage on each specimen. Compute the averagebreakdown voltage for the set, this time discarding the set.10.5.4 Using this procedure, test the remaining set
48、s until allsets have been tested twice, giving a total of ten averagebreakdown voltage measurements.NOTE 5Normally, the life end point will be reached in ten or less testsif the cycle durations of Table 1 are observed. However, if it appears thatten tests are not sufficient, as indicated by the ther
49、mal life curve, arrangeto make any further tests in triplicate on each remaining set, therebyextending the aging time.NOTE 6Because of the inherent variability of this test, it is prudent tocontinue testing until the breakdown voltage averages approach 8 kV/mm(200 V/mil) of original thickness.10.5.5 Using this procedure, repeat testing the remainingsets of specimens at the lower test temperatures.11. Calculation11.1 Establish for each temperature the thermal life curvebest fitting the plot of average dielectric breakdown voltage inkilovolts v
