1、Designation: D3251 04 (Reapproved 2013) An American National StandardStandard Test Method forThermal Endurance Characteristics of Electrical InsulatingVarnishes Applied Over Film-Insulated Magnet Wire1This standard is issued under the fixed designation D3251; the number immediately following the des
2、ignation indicates the year oforiginal adoption 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 covers the d
3、etermination of the thermalendurance characteristics of electrical insulating varnishes andfilm-insulated magnet wire in combination.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to addre
4、ss 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 practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1This test method is equivalent to IEC 60172.2. Refer
5、enced Documents2.1 ASTM Standards:2D115 Test Methods for Testing Solvent Containing Var-nishes Used for Electrical InsulationD1711 Terminology Relating to Electrical InsulationD2307 Test Method for Thermal Endurance of Film-Insulated Round Magnet Wire2.2 IEC Standard:IEC 60172 Test Procedure for the
6、 determination of thetemperature index of enameled winding wires33. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method referto Terminology D1711.4. Summary of Test Method4.1 A varnish is applied to twisted pairs of film-insulatedmagnet wire and exposed to elevated tem
7、peratures. Life testresults are compared to those of unvarnished twisted pairs.5. Significance and Use5.1 Different combinations of varnishes and film-insulatedmagnet wire behave differently when exposed to elevatedtemperatures. This includes different varnishes tested with thesame film-insulated ma
8、gnet wire and a single varnish testedwith different film-insulated magnet wire.5.2 This test method is used to determine the effect on theelectrical properties of a varnish applied to film-insulatedmagnet wire when the combination is exposed to prescribedelevated temperatures.6. Hazards6.1 It is uns
9、afe to use varnish at temperatures above theflash point without adequate ventilation, especially if thepossibility exists that flames or sparks are present. Storevarnish in sealed containers. This also applies to specifiedreagents and solvents. (WarningLethal voltages are a po-tential hazard during
10、the performance of this test. It is essentialthat the test apparatus, and all associated equipment electricallyconnected to it, be properly designed and installed for safeoperation. Solidly ground all electrically conductive partswhich it is possible for a person to contact during the test.Provide m
11、eans for use at the completion of any test to groundany parts which were at high voltage during the test or have thepotential for acquiring an induced charge during the test orretaining a charge even after disconnection of the voltagesource. Thoroughly instruct all operators as to the correctprocedu
12、res for performing tests safety. When making highvoltage tests, particularly in compressed gas or in oil, it ispossible for the energy released at breakdown to be sufficient toresult in fire, explosion, or rupture of the test chamber. Designtest equipment, test chambers, and test specimens so as tom
13、inimize the possibility of such occurrences and to eliminatethe possibility of personal injury. If the potential for fire exists,have fire suppression equipment available.)1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the di
14、rect responsibility ofSubcommittee D09.01 on Electrical Insulating Varnishes, Powders and Encapsulat-ing Compounds.Current edition approved April 1, 2013. Published April 2013. Originallyapproved in 1973. Last previous edition approved in 2009 as D3251 04 (2009).DOI: 10.1520/D3251-04R13.2For referen
15、ced 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 page onthe ASTM website.3Available from American National Standards Association, 25 W. 43rd St.,
16、4thFloor, New York, NY 10036.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Sampling7.1 Sample the varnish in accordance with Test MethodsD115.8. Test Specimen8.1 Twist two pieces of film-insulated magnet wire inaccordance with Ta
17、ble 1 on Tension and Number of Twists forTwisted Pair Construction in Test Method D2307.8.2 Use the specimen holder described in Test MethodD2307.8.3 Use one set, consisting of a minimum of ten varnishedand ten unvarnished test specimens, for each test temperature(Note 2). Eleven specimens are recom
18、mended if calculationsare to be in accordance with the median calculation method ofTest Method D2307.NOTE 2If several varnishes are being evaluated, it is necessary to runonly one set of unvarnished specimens at each temperature.9. Procedure9.1 Condition all specimens 30 to 60 min at 150 6 2C andpro
19、of test in accordance with Test Method D2307.9.2 Coat all of the specimens as follows:9.2.1 Solvent Varnishes:9.2.1.1 Adjust the consistency of solvent based varnishes togive a 0.025 6 0.0005 mm (0.001 6 0.0002 in.) build on a0.127 6 0.008 mm (0.005 6 0.0003 in.) copper strip with-drawn at a rate of
20、 90 to 110 mm/min (3.5 to 4.3 in./min). Drainfor 10 min and bake according to the suppliers recommenda-tions. Refer to Test Methods D115 for a more detailedprocedure.9.2.1.2 Immerse the specimens in the adjusted varnish, andwithdraw them at a rate of approximately 100 mm/min (4in./min). Drain for 10
21、 min and bake according to the suppliersrecommendations.9.2.1.3 Reverse the specimens end for end and repeat9.2.1.2.9.2.2 Solventless Varnishes:9.2.2.1 Test solventless varnishes in the “as made” condi-tion.9.2.2.2 The number of dips used for a solventless varnish isto be agreed upon between the int
22、erested parties. Report thenumber of dips used. If multiple dips are used, reversespecimens end for end before dipping.9.3 Place an equal number of the coated and uncoatedspecimens in the holders as described in Test Method D2307.9.4 After coating with varnish, proof test all specimens inaccordance
23、with Test Method D2307. The proof voltage isbased on the thickness of the film insulation on the magnet wireand is not dependent on the thickness of the varnish coating.9.5 Choose at least three different test temperatures fromTable 3 of Test Method D2307; age one set each of coated anduncoated spec
24、imens at each temperature. Choose the exposuretime in accordance with Test Method D2307.9.6 Test the specimens and then age them in accordancewith Test Method D2307.10. Calculation10.1 Perform the necessary calculations in accordance withTest Method D2307.11. Report11.1 Report the data as required i
25、n Test Method D2307.12. Precision and Bias12.1 PrecisionThe precision of this test method for mea-suring the thermal-aging characteristics of varnishes appliedover film-insulated magnet wire is essentially equal to theprecision stated in Test Method D2307.412.2 BiasThis test method has no bias becau
26、se thethermal-aging characteristics of varnishes applied over film-insulated magnet wire is determined solely in terms of this testmethod itself.13. Keywords13.1 magnet wire; thermal endurance; twisted pair; varnishASTM International takes no position respecting the validity of any patent rights ass
27、erted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time b
28、y the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will rece
29、ive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Inte
30、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D09-1011.D3251 04 (2013)2
