1、Designation: D2132 11An American National StandardStandard Test Method forDust-and-Fog Tracking and Erosion Resistance of ElectricalInsulating Materials1This standard is issued under the fixed designation D2132; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, 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.1. Scope1.1 This test method is intended to differentiate solid elec-trical insulating ma
3、terials with respect to their resistance to theaction of electric arcs produced by conduction through surfacefilms of a specified contaminant containing moisture. TestMethods D2302 and D2303 may also be used to evaluatematerials.1.2 The values stated in inch-pound units are the standard,except in ca
4、ses 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 practi
5、ces and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in 12.4.NOTE 1There is no equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D709 Specification for Laminated Thermosetting MaterialsD1711 Terminology Relating to
6、 Electrical InsulationD2302 Method of Test for Differential Wet Tracking Resis-tance of Electrical Insulating Materials with ControlledWater-to-Metal Discharges3D2303 Test Methods for Liquid-Contaminant, Inclined-Plane Tracking and Erosion of Insulating Materials3. Terminology3.1 Definitions:3.1.1 F
7、or definitions pertinent to this test method see Ter-minology D1711.4. High Voltage Hazard4.1 Lethal voltages are a potential hazard during the perfor-mance of this test. It is essential that the test apparatus, and allassociated equipment electrically connected to it, be properlydesigned and instal
8、led 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 completionof any test to ground any parts which were at high voltageduring the test or have the potential for acquiring an inducedcharge d
9、uring 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 safely. Whenmaking high voltage tests, particularly in compressed gas or inoil, it is possible for the energy released at breakdown
10、 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 such occur-rences and to eliminate the possibility of personal injury. If thepotential for fire exists, have fire suppression equ
11、ipmentavailable. See section 12.5. Summary of Test Method5.1 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 wetted, apply a 60-Hz voltage between theelectr
12、odes.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 carbonization concentrates the electricfield. Furt
13、her carbonization can 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 can erode under the action of the arcing. Such1This test method is under the jurisdiction of ASTM Committee
14、D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.18 on Solid Insulations, Non-Metallic Shieldings and Coveringsfor Electrical and Telecommunication Wires and Cables.Current edition approved April 15, 2011. Published June 2011. Originallyapprove
15、d in 1962. Last previous edition approved in 2003 as D213203. DOI:10.1520/D2132-11.2For 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 pa
16、ge onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.erosion usually progresses from an upper electrode through thethickn
17、ess of the specimen towards the underlying electrode.5.2 Rate materials that track in terms of the time required toform a track between the electrodes.5.3 Rate materials that do not track in terms of the timerequired to erode to failure.5.4 Failure will be indicated when the current increasessuffici
18、ently 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 trackto grow progressively over long periods of time.
19、6. Significance and Use6.1 MethodElectrical insulation in service can fail as aresult of tracking, erosion, or a combination of both, if exposedto high relative humidity and contamination environments.This is particularly true of organic insulations in outdoorapplications where the surface of the in
20、sulation becomescontaminated by deposits of moisture and dirt, for example,coal dust or salt spray. This test method is an accelerated testthat simulates extremely severe outdoor contamination. It isbelieved that the most severe conditions likely to be encoun-tered in outdoor service in the United S
21、tates will be relativelymild compared to the conditions specified in this test method.6.2 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 will be spe
22、cified in the appropriatematerial specifications, but guideline figures are suggested inNote 3. Tracking-resistant materials, unless erosion failureoccurs first, can last many hundreds of hours (Note 4). Erosion,though it can progress laterally, generally results in a failureperpendicular to the spe
23、cimen surface. Therefore, only speci-mens of the same nominal thickness can be compared forresistance to tracking-induced erosion. The extent of erosioncan be estimated from measurements of the depth of penetra-tion of the erosion. Materials that are not tracking-susceptiblecan be placed in three br
24、oad 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-susceptible mater
25、ials 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 organizedtes
26、t program among these laboratories.NOTE 5In a normal distribution approximately 68 % of all test valuesare included within 6 1 standard deviation of the mean.6.3 Interpretation of Test Results This test method pro-vides information that allows classification as described in 6.2.The comparison of mat
27、erials 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 recommende
28、d that quality levels and specificationminima be determined by statistical techniques.7. Apparatus7.1 GeneralAschematic 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 is recom
29、mended but not mandatory that aseparate power supply and control be used for each testMetric 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 SizeD2132 112specimen.
30、 This allows “breaking-in” and recording of time tofailure separately for each specimen.7.2 Circuit BreakerThe circuit breaker (current relay, OL)interrupts the power supply on failure and stops the timingmeter. It can be used as an ON-OFF switch and as a device forinterrupting air and water supply
31、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 element type, for a115-V supply. Use a resistance, R0, to shunt the current coilduring the break-in period s
32、o 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). Remove or switch out theshunt resistance after break-in.7.3 Supply Transformer4Use a supply transformer,
33、 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 whenused with a 115-V primary supply. Choose a transformer thatoffers an impedance between 600 and 1200 V resistance and200
34、 and 700 V reactance. Accomplish this by insertion ofinductance L and resistance R1in the low-voltage side andresistance R2in the high-voltage side.7.4 Control TransformerUse a variable-ratio autotrans-former, T1, to adjust the voltage as required.7.5 VoltmeterA voltmeter, V, can be used in the prim
35、aryside to determine the specimen test voltage. Alternatively ahigh-impedance voltmeter can be connected in the secondary,in which case precautions should be taken to prevent electricshock to an operator. If a voltmeter is used in the primary,calibrate it against secondary voltage with a secondary l
36、oad of10 mA.7.6 Monitoring ProvisionsUse an ac ammeter, A,tomonitor specimen current. Use a separate ammeter for each testspecimen. Alternatively make provisions to connect an amme-ter into each test-specimen circuit. Shunt the ammeter with anormally closed contact, PB, and a capacitance, C, to prot
37、ectthe 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 unless the valuesof the capacitance and ammeter impedances are such as toproduce negligible error in current measurement. Use te
38、rminalsA, 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 stop theclock if the scintillation current falls below the specified value.7.7 ElectrodesUse three copper or brass electrod
39、es12 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 a groundplate of copper or brass and of the same size as the testspecimen on the bottom surface and mounted on an insulating
40、support inclined 15 deg to the horizontal as shown in Fig. 1.4General Electric Type JE41, Model KAR-3, and Westinghouse Type VS, StyleNo. 687588, have been found satisfactory for this purpose.(a) Power supply and control circuit of wet tracking tests.(b) Air and water supply circuit.FIG. 3 Circuit D
41、iagramsFIG. 4 Clamping Arrangement for Test-Specimen ElectrodesD2132 113Clamp the electrodes firmly to the test specimen. A suggestedarrangement is shown in Fig. 4.7.8 Test ChamberUse a cubicle test chamber, Fig. 2, madefrom plastic or metal. The front wall is made of glass orpoly(methyl methacrylat
42、e), 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 tested. Three specimens requirea minimum depth of 18 in. (460 mm). Fit the chamber withmeans for venting near the
43、 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 the ambient humidity.7.8.1 Mount one or more fog nozzles (Fig. 5) to obtain thespecified uniform moisture depositi
44、on 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 approximately 14 in. (355 mm) abovethese specimens, will, with a suitably adjusted deflector,produce the specified conditions
45、 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 about double that flowingthrough a standard fog nozzle connected to an air supply of 5to 6 psig (34 to 41 kPa).7.8.2
46、 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 to thenoz
47、zle 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.8. Artificial Contaminant8.1 Use synthetic dust of the following composition:Material Parts by WeightFling (SiO2floated),A240-mesh 85Clay, 325
48、-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 Rd. (901
49、-419-7307) Paper filter pulpis satisfactory for this purpose.8.2 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.8.3 Dispense the dust from an 8-oz. (265-cm3) wide-mouthbottle covered with 40-mesh screen. A few pebbles or marblesapproximately12 in. (13 mm) in diameter will help preventscreen clogging and keep the dust mixed.8.4 Keep the dust dry prior to dispensing as well as instorage. The dust does not deteriorate upon aging if kept dry
