1、Designation: D2225 04 (Reapproved 2012)Standard Test Methods forSilicone Fluids Used for Electrical Insulation1This standard is issued under the fixed designation D2225; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast 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 These test methods cover the testing of silicone fluidsfor use in transformers, capacitors, and electronic assemblies a
3、san insulating or cooling medium, or both. These methods aregenerally suitable for specification acceptance, factory control,referee testing, and research.1.2 Although some of the test methods listed here applyprimarily to petroleum-based fluids, they are, with minorrevisions, equally applicable to
4、silicone fluids.1.3 Silicone fluids are used for electrical insulating purposesbecause of their stable properties at high and low temperaturesand their relative environmental inertness.1.4 A list of the properties and standards are as follows:Property Measured Section ASTM Test MethodPhysical:Color
5、6 D2129Flash point 7 D92Fire point 7 D92Polychlorinated biphenylcontent8 D4059Pour point 9 D97Refractive index 10 D1807Specific gravity 11 D1298, D1481, D4052Volatility 12 D4559Viscosity 13 D445, D2161Chemical:Neutralization number 14 D974Water content 15 D1533Electrical:Relative permittivity 16 D92
6、42Dielectric breakdownvoltage17 D8773Dissipation factor 18 D9242Specific resistance 19 D11692Compatibility 20 D52821.5 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
7、safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4D92 Test Method for Flash and Fire Points by ClevelandOpen Cup TesterD97 Test Method for Pour Point of Petroleum ProductsD445 Test Method for Kinematic Visco
8、sity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D877 Test Method for Dielectric Breakdown Voltage ofInsulating Liquids Using Disk ElectrodesD923 Practices for Sampling Electrical Insulating LiquidsD924 Test Method for Dissipation Factor (or Power Factor)and Relative Perm
9、ittivity (Dielectric Constant) of Electri-cal Insulating LiquidsD974 Test Method for Acid and Base Number by Color-Indicator TitrationD1169 Test Method for Specific Resistance (Resistivity) ofElectrical Insulating LiquidsD1298 Test Method for Density, Relative Density, or APIGravity of Crude Petrole
10、um and Liquid Petroleum Prod-ucts by Hydrometer MethodD1481 Test Method for Density and Relative Density (Spe-cific Gravity) of Viscous Materials by Lipkin BicapillaryPycnometerD1533 Test Method for Water in Insulating Liquids byCoulometric Karl Fischer TitrationD1807 Test Methods for Refractive Ind
11、ex and SpecificOptical Dispersion of Electrical Insulating LiquidsD1816 Test Method for Dielectric Breakdown Voltage ofInsulating Liquids Using VDE ElectrodesD2129 Test Method for Color of Clear ElectricalInsulatingLiquids (Platinum-Cobalt Scale)D2161 Practice for Conversion of Kinematic Viscosity t
12、oSaybolt Universal Viscosity or to Saybolt Furol ViscosityD2864 Terminology Relating to Electrical Insulating Liq-uids and GasesD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density Meter1These test methods are under the jurisdiction of ASTM Committee D27 onEl
13、ectrical Insulating Liquids and Gasesand are the direct responsibility of Subcom-mittee D27.02 on Gases and Non-Mineral Oil Liquids.Current edition approved May 1, 2012. Published May 2012. Originallyapproved in 1963 as D2225 63 T. Last previous edition approved in 2004 asD2225 04. DOI: 10.1520/D222
14、5-04R12.2Amodified cell cleaning procedure is given for Test Methods D924 and D1169.3A modified cell cleaning procedure is recommended for Test Method D877.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
15、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D4059 Test Method for Analysis of Polychlorinated Biphe-nyls in Insulating Liquids by Gas C
16、hromatographyD4559 Test Method for Volatile Matter in Silicone FluidD4652 Specification for Silicone Fluid Used for ElectricalInsulationD5282 Test Methods for Compatibility of Construction Ma-terial with Silicone Fluid Used for Electrical Insulation3. Terminology3.1 Definitions:3.1.1 fire pointthe t
17、emperature at which oil first ignitesand burns for at least 5 s when a small test flame is passedacross the surface under specified conditions.3.1.2 flash pointthe temperature at which vapors abovethe oil surface first ignite when a small test flame is passedacross the surface under specified condit
18、ions.3.1.3 refractive indexthe ratio of the velocity of light (of aspecified wavelength) in air at 25C to its velocity in thesubstance under test.3.1.4 specific gravitythe ratio of weight of a given volumeof material to the weight of an equal volume of water. In thismethod, both weights are correcte
19、d to weight in vacuum, andthe material is at 25C using hydrometers calibrated at 60/60F.3.1.5 volatilitythe weight of liquid lost when a specifiedweight of liquid is held at a specified elevated temperature fora specific period of time.3.1.6 water contentthe amount of water (mg/kg) dissolvedin the l
20、iquid.3.1.7 For additional terms refer to Terminology D2864.4. Significance and Use4.1 Tests covered in this standard may be used for qualitycontrol and design considerations.4.2 Included in each test method is a brief statementdescribing its significance.5. Sampling5.1 Accurate sampling, whether of
21、 the complete contents oronly parts thereof, is extremely important from the standpointof elevation of the quality of the product sampled. Obviously,examination of a sample that because of careless samplingprocedure or contamination in the sampling equipment is notdirectly representative, leads to e
22、rroneous conclusions con-cerning quality.5.2 Sample the silicone fluid in accordance with TestMethods D923.PHYSICAL METHODS6. Color6.1 Significance The chief significance of color as appliedto silicone fluid lies in the fact that if the fluid is colored, somedegree of contamination exists that may a
23、ffect the physical,chemical, and electrical properties of the fluid.6.2 ProcedureDetermine the color in accordance withTest Method D2129.7. Flash and Fire Points7.1 Significance The flash and fire points of a siliconeinsulating fluid indicates the limit to which the material may beheated, under the
24、specified test conditions, before the emittedvapors form a flammable mixture in air. Unusually low flash orfire points for a given product may indicate contamination.7.2 ProcedureDetermine the flash and fire points in ac-cordance with Test Method D92.8. Polychlorinated Biphenyl Content8.1 Scope:8.1.
25、1 Test Method D4059describes a quantitative tech-nique for determining the concentration of polychlorinatedbiphenyls (PCBs) in electrical insulating liquids.8.2 Definition:8.2.1 PCB concentrationis normally expressed in units ofparts per million (PPM) on a weight by weight basis. Standardchromatogra
26、ms of Aroclors 1242, 1254, and 1260 are used todetermine the concentration of PCB in the sample.8.3 Summary of Test MethodFollowing dilution of thesample in a suitable solvent, the solution is treated to removeinterfering substances. A small portion is then injected into apacked gas chromatographic
27、column where the components areseparated and their presence measured by an electron captureor halogen-specific electrolytic conductivity detection. Themethod is made quantitative by comparing the response of asample to that of a known quantity of one or more standardAroclors obtained under the same
28、conditions.8.4 Significance and UseUnited States regulations requirethat electrical apparatus and electrical insulating fluids contain-ing PCB be handled and disposed of through the use of specificprocedures as determined by the PCB content of the fluid. Theresults of this test method can be useful
29、in selecting appropriatehandling and disposal procedures.9. Pour Point9.1 Significance The pour point is important as an indexof the lowest temperature to which the material may be cooledwithout seriously limiting the degree of circulation of the fluid.9.2 ProcedureDetermine the pour point in accord
30、ancewith Test Method D97.10. Refractive Index10.1 Significance The refractive index is often useful forthe detection of some types of contamination and for theidentification of the molecular makeup of the various types ofsilicone insulating fluids.10.2 ProcedureDetermine the refractive index in acco
31、r-dance with Test Methods D1807.11. Specific Gravity11.1 Significance Silicone insulating fluids are usuallysold on a weight basis. The values for the specific gravitiesmust frequently be known to calculate the volume of fluidpresent at any given temperature.D2225 04 (2012)211.2 ProcedureDetermine t
32、he specific gravity in accor-dance with Test Methods D1481 or D4052 and Practice D1298.12. Volatility12.1 Significance High values may indicate contamina-tion of the silicone with other organic materials, inadequateremoval of volatile components, or contamination with adepolymerization catalyst.12.2
33、 ProcedureDetermine volatility in accordance withTest Method D4559.13. Viscosity13.1 Significance The viscosity of a silicone fluid isimportant during the process of impregnation.13.1.1 At operating temperatures the viscosity of a siliconefluid is a principal factor affecting heat transfer by convec
34、tionflow of the fluid.13.2 ProcedureDetermine the viscosity in accordancewith Test Method D445. The kinematic viscosity may beconverted to absolute viscosity in accordance with Test MethodD2161.CHEMICAL METHODS14. Neutralization Number14.1 Significance In the inspection of unused siliconefluids, the
35、 neutralization number is of importance as a qualityindex of purity. Properly refined silicone fluids are free frommineral acids and alkalies.14.1.1 Since final oxidation products of silicone fluids arenot acidic, small changes in the neutralization number of usedsilicone fluids may indicate the sol
36、ution of basic or acidicmaterials from the various solid materials in contact with thesilicone or the deterioration of such soluble materials to formbasic or acidic materials.14.2 ProcedureDetermine the neutralization number inaccordance with Test Method D974.15. Water Content15.1 Significance Under
37、 high humidity conditions, poly-dimethylsiloxane fluids can absorb moisture up to about 250ppm by weight at 25C. High levels of water content willsignificantly lower the resistivity and dielectric breakdownvoltage of the fluid.15.2 ProcedureDetermine water content in accordancewith Test Method D1533
38、.ELECTRICAL METHODS16. Relative Permittivity (Dielectric Constant)16.1 Significance Silicone insulating fluids are used toinsulate components of an electrical network from each otherand from ground. For this use, it is generally desirable to havethe capacitance as small as possible, consistent with
39、acceptablechemical properties and design considerations.16.2 ProcedureDetermine the relative permittivity in ac-cordance with Test Method D924. An alternative method ofcleaning the test cells is to use multiple rinses of isopropanolfollowed by a thorough rinsing with methylene chloride anddry with c
40、lean, dry, warm air.17. Dielectric Breakdown Voltage17.1 Significance The importance of the dielectric break-down voltage of a silicone liquid is as a measure of its abilityto withstand electrical stress without failure. It may alsoindicate the presence of contaminating materials, such aswater, cond
41、ucting solid particles, dissolved contaminants, orthe decomposition products resulting from an electric arc. Ahigh dielectric breakdown voltage, however, is not a certainindication of the absence of all contaminants.17.2 ProcedureDetermine the dielectric breakdown volt-age in accordance with Method
42、D877, with the followingmodification:17.2.1 Fill the test cup by tilting it at a 45 angle. As theliquid approaches the tilted top edge of the cup, slowly rotatethe cup to an upright position while continuing to pour sampleinto the cup. This will reduce the amount of air bubbles in thesample and prev
43、ent bubbles from being trapped under theelectrodes.17.2.2 Make one breakdown on each of the specified fillingsof the test cup.17.2.3 Clean the electrode surfaces after each breakdown byone of the following methods:17.2.3.1 Method AAfter each breakdown and before thecup is emptied, pass the electrode
44、-spacing gage through theelectrode gap twice. Then empty the cup. This will clean theelectrodes of any semisolid breakdown products and they willflow out when the cup is emptied.17.2.3.2 Method BEmpty the cup. Wipe the electrodesurfaces with a lintless paper or cloth. This is best accom-plished by f
45、olding the lintless paper over a clinical tonguedepressor. Flush the test cup with clean silicone fluid andempty the cup.17.3 Test Method D1816 may be used to determine thedielectric breakdown voltage following provided that thedischarge energy limits of Section 1.4 of the test method aremet.17.3.1
46、Determine the dielectric breakdown voltage in accor-dance with Test Method D1816.18. Dissipation (Power) Factor18.1 Significance Dissipation (power) factor of a siliconefluid is an indication of the energy dissipated as heat in thefluid. It is useful as a means for quality control and as anindicatio
47、n of changes in the fluid resulting from deterioratingand contaminating influences.18.2 ProceduresDetermine the dissipation factor in accor-dance with Test Method D924. An alternative method ofcleaning the test cells is to use multiple rinses of isopropanolfollowed by a thorough rinsing with methyle
48、ne chloride anddry with clean, dry, warm air.D2225 04 (2012)319. Specific Resistance (Resistivity)19.1 Significance The specific resistance of a siliconeinsulating fluid is a measure of its electrical insulating capa-bility in d-c apparatus. High resistivity reflects low content offree ions and ion-
49、forming particles, and normally indicates alow concentration of conductive contaminants.19.2 ProcedureWith the exception of the procedure forcleaning the test cells, determine the specific resistance inaccordance with Test Method D1169. An alternative method ofcleaning the test cells is to use multiple rinses of isopropanolfollowed by a thorough rinsing with methylene chloride anddry with clean, dry, warm air.COMPATIBILITY TESTING20. Compatibility20.1 Significance It is very important to know how otherconstruction materials will affec
