1、Designation: D 2225 04Standard Test Methods forSilicone Fluids Used for Electrical Insulation1This standard is issued under the fixed designation D 2225; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、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 These test methods cover the testing of silicone fluidsfor use in transformers, capacitors, and electronic assemblies asan insulating
3、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 silicone fluids
4、.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 6 D 2129Flash p
5、oint 7 D92Fire point 7 D92Polychlorinated biphenylcontent8 D 4059Pour point 9 D 97Refractive index 10 D 1807Specific gravity 11 D 1298, D 1481, D 4052Volatility 12 D 4559Viscosity 13 D 445, D 2161Chemical:Neutralization number 14 D 974Water content 15 D 1533Electrical:Relative permittivity 16 D 9242
6、Dielectric breakdownvoltage17 D 8773Dissipation factor 18 D 9242Specific resistance 19 D 11692Compatibility 20 D 52821.5 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-priat
7、e 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 CupD97 Test Method for Pour Point of Petroleum ProductsD 445 Test Method for Kinematic Viscosity
8、 of Transparentand Opaque Liquids (and the Calculation of DynamicViscosity)D 877 Test Method for Dielectric Breakdown Voltage ofInsulating Liquids Using Disk ElectrodesD 923 Test Methods for Sampling Electrical InsulatingLiquidsD 924 Test Method for Dissipation Factor (or Power Factor)and Relative P
9、ermittivity (Dielectric Constant) of Electri-cal Insulating LiquidsD 974 Test Method for Acid and Base Number by Color-Indicator TitrationD 1169 Test Method for Specific Resistance (Resistivity) ofElectrical Insulating LiquidsD 1298 Practice for Density, Relative Density (SpecificGravity), or API Gr
10、avity of Crude Petroleum and LiquidPetroleum Products by Hydrometer MethodD 1481 Test Method for Density and Relative Density(Specific Gravity) of Viscous Materials by Lipkin Bicap-illary PycnometerD 1533 Test Methods for Water in Insulating Liquids (KarlFischer Reaction Method)D 1807 Test Methods f
11、or Refractive Index and SpecificOptical Dispersion of Electrical Insulating LiquidsD 1816 Test Method for Dielectric Breakdown Voltage ofInsulating Oils of Petroleum Origin Using VDE ElectrodesD 2129 Test Method for Color of Water White ElectricalInsulating LiquidsD 2161 Practice for Conversion of K
12、inematic Viscosity toSaybolt Universal Viscosity or to Saybolt Furol ViscosityD 2864 Terminology Relating to Electrical Insulating Liq-uids and GasesD 4052 Test Method for Density and Relative Density ofLiquids by Digital Density Meter1These test methods are under the jurisdiction of ASTM Committee
13、D27 onElectrical Insulating Liquids and Gases and are the direct responsibility ofSubcommittee D27.02 on Synthetics.Current edition approved Dec. 1, 2004. Published January 2005. Originallyapproved in 1963 as D 2225 63 T. Last previous edition approved in 1997 asD 2225 92 (1997).2A modified cell cle
14、aning procedure is given for Test Methods D 924 andD 1169.3A modified cell cleaning procedure is recommended for Test Method D 877.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa
15、tion, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 4059 Test Method for Analysis of Polychlorinated Biphe-nyls in Insulating Liquids by Gas ChromatographyD 4559 Tes
16、t Method for Volatile Matter in Silicone FluidD 4652 Specification for Silicone Fluid Used for ElectricalInsulationD 5282 Test Methods for Compatibility of ConstructionMaterial with Silicone Fluid Used for Electrical Insulation3. Terminology3.1 Definitions:3.1.1 fire pointthe temperature at which oi
17、l 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 conditions.3.1.3 refractive
18、indexthe ratio of the velocity of light (ofa specified 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 corrected to weight in vacuum,
19、 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) dis-solved in the liquid.3.1.7 For addi
20、tional terms refer to Terminology D 2864.4. 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 the complete conte
21、nts 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 erroneous conclusion
22、s con-cerning quality.5.2 Sample the silicone fluid in accordance with TestMethods D 923.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 affect the physical
23、,chemical, and electrical properties of the fluid.6.2 ProcedureDetermine the color in accordance withTest Method D 2129.7. 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 specified test co
24、nditions, 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:8.1.1 Test Method D 4
25、059describes 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. Standardchromatograms of Aroclors 1
26、242, 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 column where the
27、 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 conditions.8.4 S
28、ignificance 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 in selecting app
29、ropriatehandling 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 accordancewith Test Me
30、thod 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 accor-dance with Tes
31、t Methods D 1807.11. 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.11.2 ProcedureDetermine the specific gravity in accor-da
32、nce with Test Methods D 1481 or D 4052 and PracticeD 1298.12. Volatility12.1 Significance High values may indicate contamina-tion of the silicone with other organic materials, inadequateD 2225 042removal of volatile components, or contamination with adepolymerization catalyst.12.2 ProcedureDetermine
33、 volatility in accordance withTest Method D 4559.13. 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 convectionflow of the fl
34、uid.13.2 ProcedureDetermine the viscosity in accordancewith Test Method D 445. The kinematic viscosity may beconverted to absolute viscosity in accordance with Test MethodD 2161.CHEMICAL METHODS14. Neutralization Number14.1 Significance In the inspection of unused siliconefluids, the neutralization
35、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 solution of basic o
36、r 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 D 974.15. Water Content15.1 Significance Under high humidity
37、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 D 1533.ELECTRICAL ME
38、THODS16. 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 acceptablechem
39、ical properties and design considerations.16.2 ProcedureDetermine the relative permittivity in ac-cordance with Test Method D 924. 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, wa
40、rm 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, conducting solid
41、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 D 877, with t
42、he 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 prevent bubbles
43、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-spacing gag
44、e 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 folding the l
45、intless paper over a clinical tonguedepressor. Flush the test cup with clean silicone fluid andempty the cup.17.3 Test Method D 1816 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 Determine t
46、he dielectric breakdown voltage in accor-dance with Test Method D 1816.18. 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 anindication of chang
47、es in the fluid resulting from deterioratingand contaminating influences.18.2 ProceduresDetermine the dissipation factor in accor-dance with Test Method D 924. An alternative method ofcleaning the test cells is to use multiple rinses of isopropanolfollowed by a thorough rinsing with methylene chlori
48、de anddry with clean, dry, warm air.19. 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-forming particles, and no
49、rmally 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 D 1169.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.D 2225 043COMPATIBILITY TESTING20. Compatibility20.1 Significance It is very important to know how otherconstruction materials will affect silicone liqui
