1、Designation: D3251 04 (Reapproved 2013)Standard 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 designation indicates the year of
2、original 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 determination of the thermalend
3、urance 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 address all of thesafety concerns,
4、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. Referenced Documents2.1 ASTM Standa
5、rds: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 determination of thetemperatu
6、re 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 temperatures. Life testresults ar
7、e 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 magnet wire and a single varnish
8、 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 unsafe to use varnish at temperat
9、ures 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 the performance of this test.
10、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 means for use at the completion
11、 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 correctprocedures for performing tests safet
12、y. 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 tominimize the possibility of suc
13、h 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 direct responsibility ofSubcommi
14、ttee 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 referenced ASTM standards, visit the
15、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., 4thFloor, New York, NY 10036.C
16、opyright 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 Table 1 on Tension and Number of
17、 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 recommended if calculationsare to b
18、e 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 andproof test in accordance with Tes
19、t 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 90 to 110 mm/min (3.5 to 4.3
20、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 min and bake according to the
21、 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 interested parties. Report thenum
22、ber 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 with Test Method D2307. The pr
23、oof 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 specimens at each temperature. Cho
24、ose 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 in Test Method D2307.12. Precis
25、ion 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 because thethermal-aging characteri
26、stics 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 asserted in connection with any i
27、tem 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 by the responsible technical co
28、mmittee 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 receive careful consideration at a
29、 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 International, 100 Barr Harbor Dri
30、ve, 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.o
31、rg). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D09-1011.D3251 04 (2013)2
