1、Designation: D 3251 04An American National StandardStandard Test Method forThermal Endurance Characteristics of Electrical InsulatingVarnishes Applied Over Film-Insulated Magnet Wire1This standard is issued under the fixed designation D 3251; the number immediately following the designation indicate
2、s 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of
3、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 as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the
4、responsibility 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 Standards:2D 115 Test Methods for Testing Solven
5、t Containing Var-nishes Used for Electrical InsulationD 1711 Terminology Relating to Electrical InsulationD 2307 Test Method for Thermal Endurance of Film-Insulated Round Magnet Wire2.2 IEC Standard:IEC 60172 Test Procedure for the determination of thetemperature index of enameled winding wires33. T
6、erminology3.1 Definitions:3.1.1 For definitions of terms used in this test method referto Terminology D 1711.4. Summary of Test Method4.1 A varnish is applied to twisted pairs of film-insulatedmagnet wire and exposed to elevated temperatures. Life testresults are compared to those of unvarnished twi
7、sted 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 testedwith different film-insulated m
8、agnet 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 temperatures above theflash point without adeq
9、uate 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. It is essentialthat the test apparatus
10、, 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 of any test to groundany parts which
11、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 safety. When making highvoltage tests, part
12、icularly 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 such occurrences and to eliminate1This te
13、st method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Varnishes, Powders, and Encapsu-lating Compounds.Current edition approved March 1, 2004. Published March 2004. Or
14、iginallyapproved in 1973. Last previous edition approved in 2003 as D 325103.2For referenced 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 ont
15、he ASTM website.3Available from American National Standards Association, 25 W. 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the possibility of personal injury. If the potential for fire exist
16、s,have fire suppression equipment available.)7. Sampling7.1 Sample the varnish in accordance with Test MethodsD 115.8. Test Specimen8.1 Twist two pieces of film-insulated magnet wire inaccordance with Table 1 on Tension and Number of Twists forTwisted Pair Construction in Test Method D 2307.8.2 Use
17、the specimen holder described in Test MethodD 2307.8.3 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 be in accordance with the median calculation method ofTest Method
18、D 2307.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 Test Method D 2307.9.2 Coat all of the specimens as follows:9.2.1 S
19、olvent 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 in./min). Drainfor 10 min and bake according to the suppliers r
20、ecommenda-tions. Refer to Test Methods D 115 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 suppliersrecommendations.9.2.1.3 Reverse the specimens end fo
21、r 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 thenumber of dips used. If multiple dips are used, reversespecimens
22、end for end before dipping.9.3 Place an equal number of the coated and uncoatedspecimens in the holders as described in Test Method D 2307.9.4 After coating with varnish, proof test all specimens inaccordance with Test Method D 2307. The proof voltage isbased on the thickness of the film insulation
23、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 D 2307; age one set each of coated anduncoated specimens at each temperature. Choose the exposuretime in accordance with Test Method D 2307.
24、9.6 Test the specimens and then age them in accordancewith Test Method D 2307.10. Calculation10.1 Perform the necessary calculations in accordance withTest Method D 2307.11. Report11.1 Report the data as required in Test Method D 2307.12. Precision and Bias12.1 PrecisionThe precision of this test me
25、thod for mea-suring the thermal-aging characteristics of varnishes appliedover film-insulated magnet wire is essentially equal to theprecision stated in Test Method D 2307.412.2 BiasThis test method has no bias because thethermal-aging characteristics of varnishes applied over film-insulated magnet
26、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 item mentionedin this standard. Users of this standard
27、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 committee and must be reviewed every five years andif no
28、t 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 meeting of theresponsible technical committee, which
29、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 Drive, PO Box C700, West Conshohocken, PA 19428-2959,Unit
30、ed 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).4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D091011.D3251042
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