1、Designation: D2303 13Standard Test Methods forLiquid-Contaminant, Inclined-Plane Tracking and Erosion ofInsulating Materials1This standard is issued under the fixed designation D2303; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 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. Scope1.1 These test methods
3、cover the evaluation of the relativetracking and erosion resistance of insulating solids using theliquid-contaminant, inclined-plane test.2The following testmethods also can be used to evaluate the tracking resistance ofmaterials: D2132 (contaminants: dust and fog) and D3638(contaminant: conductive
4、liquid drops).1.2 Two tracking and one erosion test procedure are de-scribed:1.2.1 A “variable voltage method” to evaluate resistance totracking.1.2.2 A “time-to-track method” to evaluate resistance totracking.1.2.3 A method for quantitative determination of erosion(Annex A1).1.3 While a particular
5、contaminant solution is specified,other concentrations of the same contaminant, or differentcontaminants are used to simulate different environmental orservice conditions.1.4 The values stated in inch-pound units are to be regardedas the standard.1.5 This standard does not purport to address all of
6、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. Specific precau-tionary statements are given in Section 8.2. Refere
7、nced Documents2.1 ASTM Standards:3D374 Test Methods for Thickness of Solid Electrical Insu-lation (Withdrawn 2013)4D1711 Terminology Relating to Electrical InsulationD2132 Test Method for Dust-and-Fog Tracking and ErosionResistance of Electrical Insulating MaterialsD3638 Test Method for Comparative
8、Tracking Index ofElectrical Insulating Materials2.2 IEC Standards:IEC 60587 Test Methods for Evaluating Resistance toTrack-ing and Erosion for Electrical Insulating Materials UsedUnder Severe Ambient Conditions3. Terminology3.1 Definitions:3.1.1 erosion, electrical, nthe progressive wearing awayof e
9、lectrical insulation by the action of electrical discharges.3.1.2 erosion resistance, electrical, nthe quantitative ex-pression of the amount of electrical erosion under specificconditions.3.1.3 track, na partially conducting path of localizeddeterioration on the surface of an insulating material.3.
10、1.4 tracking, nthe process that produces tracks as aresult of the action of electric discharges on or close to theinsulation surface.3.1.5 tracking, contamination, ntracking caused by scin-tillations that result from the increased surface conduction dueto contamination.3.1.6 tracking resistance, nth
11、e quantitative expression ofthe voltage and the time required to develop a track underspecified conditions.3.2 Definitions of Terms Specific to This Standard:1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct respo
12、nsibility ofSubcommittee D09.12 on Electrical Tests.Current edition approved April 1, 2013. Published June 2013. Originallyapproved in 1964. Last previous edition approved in 2004 as D2303 97 (2004),which was withdrawn in January 2013 and reinstated in April 2013. DOI:10.1520/D2303-13.2K. N. Mathes,
13、 Chapter 4, “Surface Failure Measurements,” EngineeringDielectrics, Vol IIB, Electrical Properties of Solid Insulating Materials, Measure-ment Techniques, R. Bartnikas, Editor,ASTM STP 926,ASTM, Philadelphia, 1987.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM C
14、ustomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C70
15、0, West Conshohocken, PA 19428-2959. United States13.2.1 initial tracking voltage, nthe applied voltage atwhich continuous tracking can be initiated in a specified time.3.2.2 time-to-track, nthe time in which tracking proceedsa specified distance between the test electrodes at a specifiedvoltage.3.3
16、 Other definitions pertinent to these test methods aregiven in Terminology D1711.4. Significance and Use4.1 These test methods differentiate among solid electricalinsulating materials on the basis of their resistance to the actionof voltage stresses along the surface of the solid when wet withan ion
17、izable, electrically conductive liquid contaminant.4.2 These test methods quantitatively evaluate, in a relativemanner, the effects upon an insulating material resulting fromthe action of electrical discharges upon a material surface. Theeffects are similar to those that may occur in service under t
18、heinfluence of dirt combined with moisture condensed from theatmosphere.4.2.1 In the field, the conditions resulting in electricaldischarges occur sporadically. Degradation, often in the formof a conducting “track,” develops very slowly until it ulti-mately bridges the space between conductors thus
19、causingcomplete electrical breakdown.4.2.2 In these test methods, the conducting liquid contami-nant is continuously supplied at an optimum rate to the surfaceof a test specimen in such a fashion that essentially continuouselectrical discharge can be maintained.4.2.3 By producing continuous surface
20、discharge with con-trolled energy it is possible, within a few hours, to causespecimen failure which is similar to failure occurring underlong-time exposure to the erratic conditions of service in thefield.4.2.4 The test conditions, which are standardized andaccelerated, do not reproduce all of the
21、conditions encounteredin service. Use caution when making either direct or compara-tive service behavior inferences derived from the results oftracking tests.4.3 The time-to-track a 1-in. (25-mm) distance at a specifiedvoltage between electrodes separated 2 in. (50 mm) has alsobeen found useful in c
22、ategorizing insulating materials forindoor and protected outdoor applications, such as metal-cladswitchgear.4.4 The initial tracking voltage has been found useful forevaluating insulating materials to be used at high voltages oroutdoors and unprotected, as well as for establishing (see 10.1)the test
23、 voltage for the time-to-track test.4.5 In service many types of contamination cause trackingand erosion of different materials to different degrees. Thismethod recognizes the importance of such variability andsuggests the use of special test solutions to meet specificservice needs. For example, an
24、ionic contaminant containing,in addition, a carbonaceous component such as sugar issubstituted to cause tracking on very resistant materials likepolymethylmethacrylate. Such contamination is consideredrepresentative of some severe industrial environments. In thiscase, the time-to-track technique is
25、used, since time is requiredto decompose the contaminant solution and build up conduct-ing residues on the sample surface.4.6 Very track-resistant materials, such aspolymethylmethacrylate, typically erodes rather than trackunder more usual contaminant conditions in service. The use ofthis method for
26、 measuring erosion is consequently important.For erosion studies, only tests as a function of time at constantvoltage are useful.5. Apparatus5.1 Asimple schematic diagram of the apparatus is given inFig. 1 and consists of the following. Details are given in AnnexA2.5.1.1 A 60-Hz power supply with an
27、 output voltage stabi-lized to 61 % which can be varied from 1 to at least 7.5 kVwith a rated current of no less than 0.1 A for every test stationto be used (that is, 0.5 A for five stations).5.1.2 Ameans for applying a specified contaminant solutionat a controlled rate to the specimen surface. A pn
28、eumaticallyactuated repeating pipet has been found useful for this purposeand is described in AnnexA2. Peristaltic pumps have also beenused (A2).5.1.3 Stainless steel top and bottom electrodes as shown inFig. 2.NOTE 1Stainless-steel type 302 is recommended.5.1.4 A pad of filter paper cut as shown in
29、 Fig. 3a and b tofit under the top electrode and used to smooth out the flow ofthe contaminant solution.5.1.5 Aset of ballast resistors (50, 10, and 1-krated at 200W each) to be connected as specified in series with each testspecimen on the high-voltage side of the power supply.Somewhat lower resist
30、ances are being considered by theInternational Electrotechnical Commission (IEC/TC15).5.1.6 A330-,12-W, carbon resistor5mounted with asimple tension spring and connected in series with the speci-men and ground to act as an overload, high-voltage fuse.5.1.7 Structural parts and a grounded safety encl
31、osure.5.1.8 Clip to hold the hose and filter paper in place. Fig. 3aand b shows an example of a paper clip configuration that maybe used. Other paper clip configurations may be used as long asthey do not pinch the hose affecting the contaminant flow.6. Sampling6.1 Refer to applicable materials speci
32、fications for samplinginstructions.7. Test Specimens7.1 Specimens with a flat surface measuring approximately2 5 in. (50 130 mm) as shown in Fig. 4. Measure thethickness in accordance with Test Methods D374 if there is nostandard for a particular material. Specimens must be thick5International Resis
33、tance Co. RC 20-mil type carbon-composition resistors,available from the TRW Electronics Corp., Commerce Terminal Bldg., Philadelphia,PA, have been found satisfactory.D2303 132enough that tracking does not penetrate completely through thespecimen during the test.7.1.1 Thin specimens shall be mounted
34、 on the apparatus asindividual layers (that is, samples shall not be stacked).7.1.2 Thin specimens shall be secured by mounting them ona support plaque made from an inert nonconductive material.Fig. 3a shows an example of a mounting support plaque madeout of PTFE (polytetrafluoroethylene) at an appr
35、oximate thick-ness of 6 mm.7.1.3 Care shall be exercised with thin specimens to ensurecontaminant does not flow on the back of the specimen. Thiscan lead to inconclusive results.7.2 Prepare separate specimens representative of differentsurfaces affected by anisotropy, morphology, texture, surfacetre
36、atments, pull direction, fill direction, etc. Identify the differ-ent surfaces to be tested, such as mold face, press face, texturedside, machine direction, cross-machine direction, warp or filldirection, etc. Prepare two sets of specimens of materials withnoticeable directional characteristics, wit
37、h the predominantdirectional characteristic in line with the electrodes for one setand at right angles to the other set. Identify the specimendirection such as machine direction, cross-machine direction,warp or fill direction (for woven textile reinforced products).(See Fig. 5.)7.3 Preparation of Sp
38、ecimensClean the specimen facewith a suitable solvent6and rinse with distilled water. Forspecimens to be used in the time-to-track method, do notmechanically destroy, that is, sand, abrade, and so forth. thenatural surface finish of the specimen unless otherwise speci-fied. However, with the variabl
39、e-voltage method, the surface ofthe test specimens shall be lightly but completely sanded underflowing tap water with 400A-grit wet silicon carbide paper andrinsed with distilled water. Such sanding removes gloss andcontaminants to provide a surface that is wet more easily andrapidly by the contamin
40、ant. Loss of gloss and slight erosion ofthe surface usually occurs in service, particularly outdoors.Generously cover the specimen area under the bottom elec-trode with conductive silver paint7and add the 1-in. (25-mm)tracking reference marks as shown in Fig. 5. For all tests, otherthan the time-to-
41、track test, soak the test specimens prepared asabove for 24 to 48 h in the specified contaminant solutionbefore test.7.4 Prepare five specimens for each determination.6The solvent should not soften or otherwise damage the test specimen. Isopropylalcohol has been found suitable for many materials.7Du
42、Pont silver paint No. 4817 has been found suitable for this purpose.FIG. 1 Schematic Diagram of ApparatusD2303 133FIG. 2 Top and Bottom ElectrodesFIG. 3 a Filter Paper, Clip, and Method of FasteningD2303 1348. Procedure8.1 Lethal voltages are a potential hazard during the perfor-mance of this test.
43、It is essential that the test apparatus, and allassociated equipment electrically connected to it, be properlydesigned and installed for safe operation. Solidly ground allelectrically conductive parts which it is possible for a person tocontact during the test. Provide means for use at the completio
44、nof any test to ground any parts which were at high voltageduring the test or have the potential for acquiring an inducedcharge during the test or retaining a charge even after discon-nection of the voltage source. Thoroughly instruct all operatorsas to the correct procedures for performing tests sa
45、fely. Whenmaking high voltage tests, particularly in compressed gas or inoil, it is possible for the energy released at breakdown to besufficient to result in fire, explosion, or rupture of the testchamber. Design test equipment, test chambers, and testspecimens so as to minimize the possibility of
46、such occur-rences and to eliminate the possibility of personal injury. If thepotential for fire exists, have fire suppression equipmentavailable8.1.1 Also see Fig. 1.8.2 Mount and fuse the specimen with the flat test surfaceon the underside at an angle of 45 from the horizontal asshown in Fig. 1. In
47、sert the contaminant delivery hose midwaybetween eight thicknesses of the filter paper as shown in Fig.3a and b and fold back the filter paper “ear” to preventcontaminant from squirting out the sides.8.3 At the start of each test date, replace all residual liquidin the contaminant supply beaker with
48、 fresh contaminant.Cover all beakers to minimize dust and dirt as well asevaporation. Unless otherwise specified, use 0.1 % (by weight)ammonium chloride (reagent grade) and 0.02 % (by weight)nonionic wetting agent8in distilled water. This contaminantsolution must have a resistivity between 385 6 15
49、-cm whenmeasured at 23 6 1C.8.4 Adjust the contaminant flow and calibrate as describedin AnnexA1 to give the flow rate for the voltage to be specifiedin Table 1.8.5 After calibration, the start-up procedure differs depend-ing on whether the test specimen is a carry-over from aprevious test, or an entirely new specimen.8.5.1 For a specimen that has never been subjected tovoltages and contaminant (that is, new specimen), start thecontaminant injection into the filter paper, allowing the freshcontaminant to wet the filter paper thoroughly and replace theold liqu
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