1、Designation: D 2132 03An American National StandardStandard Test Method forDust-and-Fog Tracking and Erosion Resistance of ElectricalInsulating Materials1This standard is issued under the fixed designation D 2132; the number immediately following the designation indicates the year oforiginal adoptio
2、n 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.1. Scope1.1 This test method is intended to differentiate solid elec-trical insulating
3、 materials with respect to their resistance to theaction of electric arcs produced by conduction through surfacefilms of a specified contaminant containing moisture. TestMethods D 2302 and D 2303 may also be used to evaluatematerials.1.2 The values stated in inch-pound units are the standard,except
4、in cases where SI units are more appropriate. The valuesin parentheses are for information only.1.3 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 p
5、ractices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in 11.4.NOTE 1There is no equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D 709 Specification for Laminated Thermosetting MaterialsD 1711 Terminology Rela
6、ting to Electrical InsulationD 2302 Method of Test for Differential Wet Tracking Re-sistance of Electrical Insulating Materials with ControlledWater-to-Metal Discharges3D 2303 Test Methods for Liquid-Contaminant, Inclined-Plane Tracking and Erosion of Insulating Materials3. Terminology3.1 Definition
7、s:3.1.1 For definitions pertinent to this test method see Ter-minology D 1711.4. Summary of Test Method4.1 With electrodes mounted as shown in Fig. 1, coat testspecimens with a synthetic dust and test in a chamber shown inFig. 2. Direct a water spray at the test specimen. After thesurface has been w
8、etted, apply a 60-Hz voltage between theelectrodes. Arcing occurs across localized high-resistance areasproduced by nonuniform evaporation of the water from thecontaminant. These arcs produce high temperatures in theunderlying insulation with resultant carbonization of mostorganic materials. The car
9、bonization concentrates the electricfield. Further carbonization may occur in the direction of thefield. In such cases, a carbon track is formed which spans thedistance between the electrodes and causes failure. Materialsthat do not track may erode under the action of the arcing. Sucherosion usually
10、 progresses from an upper electrode through thethickness of the specimen towards the underlying electrode.4.2 Rate materials that track in terms of the time required toform a track between the electrodes.4.3 Rate materials that do not track in terms of the timerequired to erode to failure.4.4 Failur
11、e will be indicated when the current increasessufficiently to actuate an overcurrent device.NOTE 2The conditions of this test favor the formation of a track forseveral possible reasons. Most important, the continuous renewal of theconducting properties of the contaminant by the water spray allows a
12、trackto grow progressively over long periods of time.5. Significance and Use5.1 MethodElectrical insulation in service may fail as aresult of tracking, erosion, or a combination of both, if it isexposed to high relative humidity and contamination environ-ments. This is particularly true of organic i
13、nsulations inoutdoor applications where the surface of the insulation be-comes contaminated by deposits of moisture and dirt, forexample, coal dust or salt spray. This test method is anaccelerated test that simulates extremely severe outdoor con-tamination. It is believed that the most severe condit
14、ions likelyto be encountered in outdoor service in the United States willbe relatively mild compared to the conditions specified in thistest method.1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSu
15、bcommittee D09.18 on Solid Insulations, Non-Metallic Shieldings, and Cover-ings for Electrical and Telecommunications Wires and Cables.Current edition approved Oct. 1, 2003. Published December 2003. Originallyapproved in 1962. Last previous edition approved in 1998 as D 2132 98.2For referenced ASTM
16、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.3Discontinued, see 1982 Annual Book of ASTM Standards, Part 39.1Copyright ASTM Int
17、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Test ResultsMaterials can be classified by this testmethod as tracking-resistant, tracking-affected, or tracking-susceptible. The exact test values for these categories as theyapply to specific uses w
18、ill be specified in the appropriatematerial specifications, but guideline figures are suggested inNote 3. Tracking-resistant materials, unless erosion failureoccurs first, may last many hundreds of hours (Note 4).Erosion, though it may progress laterally, generally results in afailure perpendicular
19、to the specimen surface. Therefore, onlyspecimens of the same nominal thickness may be compared forresistance to tracking-induced erosion. The extent of erosionmay be estimated from measurements of the depth of penetra-tion of the erosion. Materials that are not tracking-susceptiblemay be placed in
20、three broad categorieserosion-resistant,erosion-affected, and erosion-susceptible. When the standardthickness specimen is tested, the following times to failuretypify the categories (Note 5):Erosion-susceptible 5 to 50 hErosion-affected 50 to 200 hErosion-resistant over 200 hNOTE 3Tracking-susceptib
21、le materials usually fail within 5 h.Tracking-affected materials usually fail before about 100 h.NOTE 4This information is derived from the individual experiencesof eight laboratories using this test method since its publication as asuggested test method in June 1957, and from the results of an orga
22、nizedtest program among these laboratories.NOTE 5In a normal distribution approximately 68 % of all test valuesare included within 6 1 standard deviation of the mean.5.3 Interpretation of Test Results This test method pro-vides information that allows classification as described in 5.2.The compariso
23、n of materials within the same group is likely tobe ambiguous unless three or more replicate specimens aretested. When the test method is used for specification purposes,simple minimum values should not be established withoutconsideration of the large variance to be expected in testresults. It is re
24、commended that quality levels and specificationminima be determined by statistical techniques.6. Apparatus6.1 GeneralA schematic diagram of the power supply andcontrol apparatus for testing one specimen is shown in Fig.3(a). It is generally desirable to test three or more specimenssimultaneously. It
25、 is recommended but not mandatory that aseparate power supply and control be used for each testspecimen. This allows “breaking-in” and recording of time tofailure separately for each specimen.6.2 Circuit BreakerThe circuit breaker (current relay, OL)interrupts the power supply on failure and stops t
26、he timingmeter. It may be used as an ON-OFF switch and as a device forinterrupting air and water supply when all specimens fail. Fig.3(b) illustrates the air and water supply circuit when threespecimens are tested using one fog nozzle. The circuit breakershall be rated at 2 to 3 A, inverse-time elem
27、ent type, for a115-V supply. Use a resistance, R0, to shunt the current coilduring the break-in period so that the breaker will not actuateas a result of the bright-flash currents typical of this period.Adjust the resistance to produce an effective breaker action atapproximately 6 A (115-V supply).
28、Remove or switch out theshunt resistance after break-in.Metric Equivalentsin.1812 12mm 3.2 12.7 25.4 50.8FIG. 1 Test Arrangement of Electrode System18 in. = 458 mm 20 in. = 508 mm 28 in. = 712 mmFIG. 2 Dust and Fog Test Chamber,Minimum Recommended Size(a) Power supply and control circuit of wet trac
29、king tests.(b) Air and water supply circuit.FIG. 3 Circuit DiagramsD21320326.3 Supply Transformer4Use a supply transformer, T2,capable of supplying 1500 V, 60 Hz, rms. A200-VA potentialtransformer is capable of supplying power for up to threespecimens if desired. Use a transformer with a 20:1 ratio
30、whenused with a 115-V primary supply. Choose a transformer thatoffers an impedance between 600 and 1200 V resistance and200 and 700 V reactance. Accomplish this by insertion ofinductance L and resistance R1in the low-voltage side andresistance R2in the high-voltage side.6.4 Control TransformerUse a
31、variable-ratio autotrans-former, T1, to adjust the voltage as required.6.5 VoltmeterA voltmeter, V, may be used in the primaryside to determine the specimen test voltage. Alternatively ahigh-impedance voltmeter may be connected in the secondary,in which case precautions should be taken to prevent el
32、ectricshock to an operator. If a voltmeter is used in the primary,calibrate it against secondary voltage with a secondary load of10 mA.6.6 Monitoring Provisions Use an ac ammeter, A,tomonitor specimen current. Use a separate ammeter for each testspecimen. Alternatively make provisions to connect an
33、amme-ter into each test-specimen circuit. Shunt the ammeter with anormally closed contact, PB, and a capacitance, C, to protectthe ammeter from the large intermittent currents that occurduring break-in. Connect the capacitance, if used, by a switch,SA. After the break-in period, open the switch unle
34、ss the valuesof the capacitance and ammeter impedances are such as toproduce negligible error in current measurement. Use terminalsA, B and C, D for oscilloscope monitoring, for currentmeasurement with a voltmeter in combination with a resistor,or for insertion of an undercurrent relay to be used to
35、 stop theclock if the scintillation current falls below the specified value.6.7 ElectrodesUse three copper or brass electrodes12 by2by18 in. (13 by 51 by 3.2 mm), with corners rounded to a18-in. (3.2-mm) radius on the top surface of the specimen andspaced 1 in. (25 mm) apart as shown in Fig. 1. Use
36、a groundplate of copper or brass and of the same size as the testspecimen on the bottom surface and mounted on an insulatingsupport inclined 15 deg to the horizontal as shown in Fig. 1.Clamp the electrodes firmly to the test specimen. A suggestedarrangement is shown in Fig. 4.6.8 Test ChamberUse a c
37、ubicle test chamber, Fig. 2, madefrom plastic or metal. The front wall is made of glass orpoly(methyl methacrylate), or contains viewing ports or doorsmade of these materials. Make the cubicle at least 20 in. (510mm) high and 28 in. (710 mm) wide. Determine the depth bythe number of specimens to be
38、tested. Three specimens requirea minimum depth of 18 in. (460 mm). Fit the chamber withmeans for venting near the bottom of the cubicle, preferablyalong the end of the chamber where the specimens are located.Limit the venting area to about 20 in.2(130 cm2) to eliminatedependence of test results on t
39、he ambient humidity.6.8.1 Mount one or more fog nozzles (Fig. 5) to obtain thespecified uniform moisture deposition on all test specimens. Itis suggested that one fog nozzle, mounted approximately 25 in.(635 mm) straight line distance from the nozzle to the centerspecimen at a height of approximatel
40、y 14 in. (360 mm) abovethese specimens, will, with a suitably adjusted deflector,produce the specified conditions for three test specimens in asingle cubicle (see Fig. 2). When only one fog nozzle is usedin the cubicle, it is recommended that additional air beintroduced into the cubicle equal to abo
41、ut double that flowing4General Electric Type JE41, Model KAR-3, and Westinghouse Type VS, StyleNo. 687588, have been found satisfactory for this purpose.FIG. 4 Clamping Arrangement for Test-Specimen ElectrodesD2132033through a standard fog nozzle connected to an air supply of 5to 6 psig (34 to 41 kP
42、a).6.8.2 Connect the fog nozzle assembly,5Fig. 6, to an air andwater supply. Provide means to adjust the air supply to 5 to 6psig. Supply the water from a reservoir mounted below thenozzle so that the water level is approximately 5 in. (125 mm)below the nozzle. Use a needle valve in the water line t
43、o thenozzle to control the rate of fog deposition. To ensure uninter-rupted flow of the water to the nozzle, filter the water toremove the dissolved air in the water.7. Artificial Contaminant7.1 Use synthetic dust of the following composition:Material Parts by WeightFling (SiO2floated),A240-mesh 85C
44、lay, 325-meshB9Salt (NaCl), technical grade 3Paper, filter pulpC3AFisher Scientific Co. Catalog No. S153-3 (SPD S-S3) is satisfactory for thispurpose.BR. E. Carroll, Inc., Trenton, NJ (1-800-257-9365) Suwanee Clay (325 mesh) issatisfactory for this purpose.CInternational Paper Co., 2 Manhattenville
45、Rd. (901-419-7307) Paper filter pulpis satisfactory for this purpose.7.2 Mix the dust components in a ball mill with approxi-mately 1-in. (25-mm) diameter flint pebbles to the consistencyof a fine talcum. Milling for 72 h is usually sufficient.7.3 Dispense the dust from an 8-oz. (265-cm3) wide-mouth
46、bottle covered with 40-mesh screen. A few pebbles or marblesapproximately12 in. (13 mm) in diameter will help preventscreen clogging and keep the dust mixed.7.4 Keep the dust dry prior to dispensing as well as instorage. The dust has not been found to deteriorate upon agingif kept dry.8. Sampling8.1
47、 Refer to applicable material specification for samplinginstructions.9. Test Specimens9.1 Prepare a test specimen between 5 by 5 in. (127 by 127mm) and 6 by 6 in. (152 by 152 mm) and of the thicknessspecified.9.2 The standard specimen thickness is 0.0625 6 0.005 in.(1.6 6 0.1 mm). Always use this th
48、ickness when it is desiredto determine the erosion resistance of tracking-resistant mate-rials.9.3 The specimen may be up to14 in. (6-mm) thick when itis desired to determine the tracking resistance of materials thatare not tracking-susceptible.NOTE 6Some specimens may not track even when using a14-
49、in.thickness but may fail by erosion. In this event, report the trackingresistance as greater than the time required to produce erosion failure.Report the erosion resistance as the time to erosion failure of the standardspecimen (0.0625 in.,1.6 mm).10. Calibration10.1 Periodically perform control tests on reference materi-als to demonstrate that the test equipment and procedure are inconformity with established standards. The following referencematerials are recommended:10.1.1 Polystyrene, failure by tracking in less than 1.5 h.10.1.2 Melamine glass, Grade G
