ASTM D115-17 Standard Test Methods for Testing Solvent Containing Varnishes Used for Electrical Insulation.pdf

1、Designation: D115 17Standard Test Methods for TestingSolvent Containing Varnishes Used for Electrical Insulation1This standard is issued under the fixed designation D115; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of

2、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. Scope*1.1 These test methods cover tests for solvent containingvarnishes primarily intended to provide electrical, mechanical,a

3、nd chemical protection for electrical equipment. These testmethods include tests for control and performance as follows:Procedure SectionBuild 3842Dielectric Strength 4348Drainage 2632Flash Point 1820Nonvolatile Matter 2125Oil Resistance 5456Preparation of Test Specimens 7Specific Gravity 912Tempera

4、ture Index 49 50Time of Drying 3337Varnish Compatibility 5153Viscosity 13171.2 Where the entire test method is included in this standard,the precision and bias are not known unless given in the statedmethod.1.3 The values stated in SI units are to be regarded asstandard. The values given in parenthe

5、ses are for informationonly.1.4 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, health, and environmental practices and deter-mine the applicability of regulat

6、ory limitations prior to use.For specific hazard statements, see Section 5.NOTE 1There is no equivalent IEC standard.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopmen

7、t of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D56 Test Method for Flash Point by Tag Closed Cup TesterD93 Test Methods for Flash Point by Pensky-MartensClosed Cup

8、TesterD149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD202 Test Methods for Sampling and Testing UntreatedPaper Used for Electrical InsulationD287 Test Method for API Gravity of Crude Petroleum andPetrole

9、um Products (Hydrometer Method)D295 Test Methods for Varnished Cotton Fabrics Used forElectrical InsulationD374 Test Methods for Thickness of Solid Electrical Insu-lation (Metric) D0374_D0374MD580 Specification for Greige Woven Glass Tapes andWebbingsD1475 Test Method for Density of Liquid Coatings,

10、 Inks,and Related ProductsD1932 Test Method for Thermal Endurance of FlexibleElectrical Insulating VarnishesD2518 Specification for Woven Glass Fabrics for ElectricalInsulation (Withdrawn 2013)3D2519 Test Method for Bond Strength of Electrical Insulat-ing Varnishes by the Helical Coil TestD3145 Test

11、 Method for Thermal Endurance of ElectricalInsulating Varnishes by the Helical Coil MethodD3251 Test Method for Thermal Endurance Characteristicsof Electrical Insulating Varnishes Applied Over Film-Insulated Magnet WireD3278 Test Methods for Flash Point of Liquids by SmallScale Closed-Cup ApparatusD

12、3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD5032 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Glycerin Solutions1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the di

13、rect responsibility ofSubcommittee D09.01 on Electrical Insulating Products.Current edition approved Nov. 1, 2017. Published November 2017. Originallyapproved in 1941. Last previous edition approved in 2014 as D115 14. DOI:10.1520/D0115-17.2For referenced ASTM standards, visit the ASTM website, www.

14、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.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears

15、 at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles

16、 for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.145 D5423 Specification for Forced-Convection Laboratory Ov-ens for Evaluation of Electrical InsulationE104 Practice for Maintaining Constant

17、Relative Humidityby Means of Aqueous Solutions3. Terminology3.1 Definitions:3.1.1 dielectric strength, nthe voltage gradient at whichdielectric failure of the insulating material occurs under spe-cific conditions of test.3.1.2 drainage, nof an insulating varnish, a measure ofthe variation in thickne

18、ss from top to bottom of a varnish filmobtained on the surface of a vertically dip-coated panel after aspecified time and temperature.3.1.3 flash point, nthe lowest temperature of thespecimen, corrected to a pressure of 760 mm Hg (101.3 kPa),at which application of an ignition source causes any vapo

19、rfrom the specimen to ignite under specified conditions of test.3.1.4 nonvolatile matter, nin insulating varnish, that por-tion of a varnish which is not volatilized when exposed tospecified conditions; the value obtained is not necessarily equalto the calculated solids incorporated during compoundi

20、ng.3.1.4.1 DiscussionFor example, the theoretical chemicalsolids are often assumed to be the solid phase materialsincorporated in the varnish at the time of compounding. Manyof these solid phase intermediate materials will lose volatilefractions due to the specified conditions of the nonvolatilematt

21、er procedure. An example is phenolic resin.3.1.5 oil resistance, nof insulating varnish, a measure ofthe retention of properties after exposure to a specified oilunder specified conditions of test.3.1.6 time of drying, nof insulating varnish, the timerequired for a film of varnish to dry to a tackfr

22、ee state underspecified conditions.3.2 Definitions of Terms Specific to This Standard:3.2.1 build, nof an insulating varnish on copper, theaverage thickness of varnish film on one side of a copper panelthat has received a single coat of the varnish applied andmeasured under specified conditions.3.2.

23、2 build, nof an insulating varnish on glass cloth, theaverage overall thickness of strips of glass cloth that havereceived two dips of the varnish applied and measured underspecified conditions.3.2.3 tack-free, adjcondition when a varnish has reachedthe point that the surface can be touched lightly

24、without asensation of stickiness.3.2.4 varnish, air-drying, na liquid resin system thatforms a dry, tack-free coating, without the application of heat,either through evaporation of solvent or by reaction withatmospheric oxygen.3.2.5 varnish, baking, na liquid resin system that forms adry, tack-free

25、coating when exposed to elevated temperatures.4. Significance and Use4.1 ControlThe following tests are useful for controlpurposes during the manufacture and use of varnishes, and fordetermining the uniformity of batches:4.1.1 Specific gravity,4.1.2 Viscosity,4.1.3 Flash point, and4.1.4 Nonvolatile

26、matter by weight.4.2 PerformanceThe following tests are useful for deter-mining the performance of varnishes during application anduse:4.2.1 Drainage,4.2.2 Time of drying,4.2.3 Build,4.2.4 Dielectric strength,4.2.5 Thermal endurance,4.2.6 Varnish compatibility,4.2.7 Salt water proofness, and4.2.8 Oi

27、l resistance.5. Hazards5.1 WarningDo not use varnish at temperatures abovethe flash point when inadequate ventilation and the possibilityof flames or sparks exist. Store varnish in sealed containers.The precautions shall also apply to the handling of the reagentsand solvents called for herein.6. Sam

28、pling6.1 For all tests the sample shall be taken from a represen-tative lot of the varnish under study. To avoid skin formationand escape of solvents, protect the sample by keeping it atroom temperature in a nearly filled, tightly sealed container.7. Preparation of Test Specimens7.1 Selection of Sub

29、strateThe selection of the substrate isdetermined in part by application and in part by thermal class.Two types of substrates are suitable for use: copper strip orglass cloth. Copper strip is generally not used for applicationsover 180C (356F), due to oxidation.7.2 Copper BaseFor tests that are to b

30、e performed uponthe varnish as a film on a copper base, copper strips 38 mm(112 in.) in width, 200 mm (8 in.) in length, and 0.127 60.08 mm (0.005 6 0.0003 in.) in thickness shall be used,unless otherwise specified. Measure the thickness of thesestrips to the nearest 0.002 mm (0.0001 in.). Clean the

31、 stripswith a suitable solvent (Note 2), then polish thoroughly withNo. 000 steel wool. Wipe the strips free of any fingerprints ormetal particles with the solvent and a lint-free cloth. If thestrips are not to be used immediately, store in a noncorrosivevarnish solvent.NOTE 2Xylene and denatured al

32、cohol (1:1) have been found to besuitable cleaning solvents. V.M.&.P. naphtha is a suitable solvent in whichto store the strips.7.2.1 Prepare all varnish films for tests at 23 6 1C (73.5 62F) and 50 6 5 % relative humidity. The air of the room shallbe relatively free of dust by some satisfactory met

33、hod offiltering.7.2.2 After the strips have been wiped clean and dry,prepare the test specimens by dipping them into a tank of thevarnish that has been adjusted to a proper consistency andallowed to stand covered until free of bubbles (not to exceedD115 17245 1 h). Trial testing is required to estab

34、lish the proper consis-tency. Proper consistency has been reached when the strips aredipped in the varnish at a temperature of 23 6 1C (73.5 62F) and are withdrawn slowly and uniformly at the rate of 100mm (4 in.)/min., the average thickness of the film remaining oneach side of a strip when dry shal

35、l be 0.025 6 0.005 mm(0.0010 6 0.0002 in.).7.2.3 Calculate the average thickness by averaging at leastsix measurements taken along the length of the strip and over3mm(18 in.) from either edge. Thickness measurements shallbe made in accordance with Test Methods D374.7.2.4 It is recognized that the th

36、ickness of the film cannot bemeasured with the precision stated, but a close control of thethickness of the varnish film is desired. With the methodspecified, the actual average thickness is within 60.005 mm(60.0002 in.) of the measured thickness.7.2.5 With air dry varnishes, except where time of dr

37、ying isthe property being measured, following each dip, suspend thespecimens vertically in a dipping position and dry in dust-freeair for such times and at such temperatures as the user and thesupplier agree are suitable. If necessary, readjust the consis-tency of the varnish and dip the specimen in

38、 the reversedirection to the first and air dry.7.2.6 With baking varnishes, allow the specimens to drain ata temperature of 23 6 1C (73.5 6 2F), then bake for suchtimes and at such temperatures as the user and the supplieragree are suitable. If necessary, readjust the consistency of thevarnish and d

39、ip the specimen in the reverse direction to the firstand bake.7.3 Glass Cloth Base:7.3.1 For tests that are to be performed on the varnish as acombination with glass cloth, use a glass strip instead of acopper strip. Prepare the strip from specimens 38 mm (1.5 in.)wide by approximately 250 mm (10 in

40、.) long from heat-cleaned woven glass fabric (Note 3). The length shall be in thedirection of the warp threads. The fabric shall be Style No. 116as listed in Table 1 of Specification D2518. The volatile contentof the heat-cleaned fabric shall not exceed 0.1 % as determinedin accordance with the orga

41、nic content test of SpecificationD580 (Note 4). The strip form specimens shall be kept in aStandard Laboratory Atmosphere (see 7.2.1).7.3.2 Condition the heat-cleaned glass strips1hat105C(221F) and cool in a Standard Laboratory Atmosphere beforecoating.NOTE 3One method of creating the strip form spe

42、cimens is bystamping out of the woven glass fabric by means of die and clicker. Thistechnique causes the ends of the fibers to bind together and prevents theunraveling of the yarn.NOTE 4Commercially heat-cleaned fiberglass fabric meeting thisvolatile content is available.7.3.3 Dipping and CuringCond

43、ition the varnish to betested for a minimum of4hatStandard Laboratory Tempera-ture before coating the strips. Immerse specimens in thevarnish until bubbling stops. Withdraw at 100 mm (4 in.)/min.and drain in a dipping and draining chamber in the sameposition as dipped for 30 min., or as agreed betwe

44、en the userand supplier. In order to facilitate dipping and curing and toobtain smoother specimens, secure the fiberglass strips at theends to rectangular wire frames about 240 by 70 mm (9.5 by2.75 in.). Bake specimens for the time and at the temperaturespecified by the manufacturer for the first co

45、at. Apply the nextcoat by reverse dipping, except withdraw specimens as soon asimmersed and drain as for the previous coat. Bake the secondcoat in accordance with the manufacturers recommendedschedule for a final coat.7.3.4 Measuring Specimen ThicknessMeasure specimenthickness using a dead-weight di

46、al-type micrometer in accor-dance with Test Methods D374, Method C, except that theweight on the specimen shall be limited to 567 6 7 g (20 60.25 oz.) and the anvil surface upon which the specimen restsshall be 51 mm (2 in.) in diameter. Allow the presser foot toremain on the specimens about 2 s bef

47、ore taking a reading.Where thickness measurements along a line or in an area arenonuniform, repeat the measurements, taking care to avoid filmabnormalities.8. Conditioning8.1 Condition the specimens as described in the individualtest procedures.SPECIFIC GRAVITY9. Terminology9.1 Definitions:9.1.1 spe

48、cific gravitythe ratio of the weight of a unitvolume of sample as compared with the weight of the sameunit volume of distilled water at 23 6 1C (73.5 6 2F).10. Significance and Use10.1 Specific gravity indicates the relative weight per unitvolume of a varnish. It is a useful test for control purpose

49、s.11. Procedure11.1 Determine the specific gravity of the varnish by usinga wide-mouth pycnometer (25-mL minimum capacity) at 23 61C (73.5 6 2F). Refer to Test Method D1475. Determine thespecific gravity by dividing the weight of an equal volume ofdistilled water at the same temperature.11.2 A hydrometer is another method for determining thisproperty, in accordance with Test Method D287.12. Report12.1 Report the following information:12.1.1 Identification of the varnish used, and12.1.2 The specific gravity at 23 6 1C (7