1、Designation: D3251 04 (Reapproved 2013)D3251 19Standard 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
2、 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. Scope Scope*1.1 This test method covers the determination of
3、 the thermal endurance characteristics of electrical insulating varnishes andfilm-insulated magnet wire in combination.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of th
4、e safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.NOTE 1This test method is equivalent to IEC
5、 60172.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barrier
6、s to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D115 Test Methods for Testing Solvent Containing Varnishes Used for Electrical InsulationD1711 Terminology Relating to Electrical InsulationD2307 Test Method for Thermal Endurance of Film-Insulated Round Magnet Wire2.2 IEC Standar
7、d:IEC 60172 Test Procedure for the determination of the temperature index of enameled winding wires33. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method refer to Terminology D1711.4. Summary of Test Method4.1 A varnish is applied to twisted pairs of film-insulated ma
8、gnet wire and exposed to elevated temperatures. Life test resultsare compared to those of unvarnished twisted pairs.5. Significance and Use5.1 Different combinations of varnishes and film-insulated magnet wire behave differently when exposed to elevatedtemperatures. This includes different varnishes
9、 tested with the same film-insulated magnet wire and a single varnish tested withdifferent film-insulated magnet wire.5.2 This test method is used to determine the effect on the electrical properties of a varnish applied to film-insulated magnetwire when the combination is exposed to prescribed elev
10、ated temperatures.1 This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of SubcommitteeD09.01 on Electrical Insulating Varnishes, Powders and Encapsulating CompoundsProducts.Current edition approved April
11、 1, 2013Jan. 1, 2019. Published April 2013January 2019. Originally approved in 1973. Last previous edition approved in 20092013 asD3251 04 (2009).(2013). DOI: 10.1520/D3251-04R13.10.1520/D3251-19.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at
12、serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Association, 25 W. 43rd St., 4th Floor, New York, NY 10036.This document is not an ASTM standard and is intended only to
13、 provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof
14、 the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Hazards6.1 It is unsafe to use varnish at
15、 temperatures above the flash point without adequate ventilation, especially if the possibilityexists that flames or sparks are present. Store varnish in sealed containers. This also applies to specified reagents and solvents.(WarningLethal voltages are a potential hazard during the performance of t
16、his test. It is essential that the test apparatus, andall associated equipment electrically connected to it, be properly designed and installed for safe operation. Solidly ground allelectrically conductive parts which it is possible for a person to contact during the test. Provide means for use at t
17、he completionof any test to ground any parts which were at high voltage during the test or have the potential for acquiring an induced chargeduring the test or retaining a charge even after disconnection of the voltage source. Thoroughly instruct all operators as to thecorrect procedures for perform
18、ing tests safety. When making high voltage tests, particularly in compressed gas or in oil, it ispossible for the energy released at breakdown to be sufficient to result in fire, explosion, or rupture of the test chamber. Designtest equipment, test chambers, and test specimens so as to minimize the
19、possibility of such occurrences and to eliminate thepossibility of personal injury. If the potential for fire exists, have fire suppression equipment available.)7. Sampling7.1 Sample the varnish in accordance with Test Methods D115.8. Test Specimen8.1 Twist two pieces of film-insulated magnet wire i
20、n accordance with Table 1 on Tension and Number of Twists for TwistedPair Construction in Test Method D2307.8.2 Use the specimen holder described in Test Method D2307.8.3 Use one set, consisting of a minimum of ten varnished and ten unvarnished test specimens, for each test temperature (Note2). Elev
21、en specimens are recommended if calculations are to be in accordance with the median calculation method of Test MethodD2307.NOTE 2If several varnishes are being evaluated, it is necessary to run only one set of unvarnished specimens at each temperature.9. Procedure9.1 Condition all specimens 30 to 6
22、0 min at 150 6 2C and proof 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 to give a 0.025 6 0.0005 mm (0.001 6 0.0002 in.) build on a 0.1276 0.008 mm (0.005 6 0.0003 in.) copper str
23、ip withdrawn at a rate of 90 to 110 mm/min (3.5 to 4.3 in./min). Drain for 10 minand bake according to the suppliers recommendations. Refer to Test Methods D115 for a more detailed procedure.9.2.1.2 Immerse the specimens in the adjusted varnish, and withdraw them at a rate of approximately 100 mm/mi
24、n (4(4 in.in./min). min). Alternately, specimens may be coated by trickling. The specimens are held in a fixture horizontal and the resin isapplied along the length of the twisted sectioned and part way up the legs. Drain for 10 min and bake in the direction processedand according to the suppliers r
25、ecommendations.9.2.1.3 Reverse the specimens end for end for specimens processed vertically and repeat 9.2.1.2. For horizontally processedspecimens, flip specimens over so that the original side up is down and repeat 9.2.1.2.9.2.2 Solventless Varnishes:9.2.2.1 Test solventless varnishes in the “as m
26、ade” condition.9.2.2.2 The number of dips used for a solventless varnish is to be agreed upon between the interested parties. Report the numberof dips used. If multiple dips are used, reverse specimens end for end before dipping.9.2.2.3 Process specimens using solventless varnish, as described in 9.
27、2.1.2 and 9.2.1.3.9.3 Place an equal number of the coated and uncoated specimens in the holders as described in Test Method D2307. for a directcomparison. In some cases, the thermal characteristics of the magnet wire is well known and testing is not required to gain usefulcomparative data.9.4 After
28、coating with varnish, proof test all specimens in accordance with Test Method D2307. The proof voltage is based onthe thickness of the film insulation on the magnet wire and is not dependent on the thickness of the varnish coating.9.5 Choose at least three different test temperatures from Table 3 of
29、 Test Method D2307; age one set each of coated anduncoated specimens at each temperature. Choose the exposure time in accordance with Test Method D2307.9.6 Test the specimens and then age them in accordance with Test Method D2307.10. Calculation10.1 Perform the necessary calculations in accordance w
30、ith Test Method D2307.D3251 19211. Report11.1 Report the data as required in Test Method D2307.12. Precision and Bias12.1 PrecisionThe precision of this test method for measuring the thermal-aging characteristics of varnishes applied overfilm-insulated magnet wire is essentially equal to the precisi
31、on stated in Test Method D2307.412.2 BiasThis test method has no bias because the thermal-aging characteristics of varnishes applied over film-insulatedmagnet wire is determined solely in terms of this test method itself.13. Keywords13.1 magnet wire; thermal endurance; twisted pair; varnishSUMMARY O
32、F CHANGESCommittee D09 has identified the location of selected changes to this standard since the last issue (D3251 04(2013) that may impact the use of this standard. (Approved Jan. 1, 2019.)(1) Updated 9 to allow for alternate processing method.ASTM International takes no position respecting the va
33、lidity of any patent rights asserted 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 su
34、bject to revision at any time by 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 Headqua
35、rters. Your comments will receive 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 standa
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37、iceastm.org (e-mail); or through the ASTM website(www.astm.org). 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:/ Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D09-1011.D3251 193
