1、Designation: D4880 08D4880 14 An American National StandardStandard Test Method forSalt Water Proofness of Insulating Varnishes OverEnamelled Magnet Wire1This standard is issued under the fixed designation D4880; the number immediately following the designation indicates the year oforiginal adoption
2、 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*1.1 This test method covers the electrical performance in a specified water sol
3、ution of an insulating varnish applied overenamelled magnet wire.1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversionsto inch-pound units that are provided for information only and are not considered standard.1.3 This standard
4、does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements
5、are given in Section 6.NOTE 1There is no IEC method equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D1676 Test Methods for Film-Insulated Magnet WireD1711 Terminology Relating to Electrical Insulation3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this tes
6、t method refer to Terminology D1711.3.1.2 varnish, electrical insulating, n a liquid resin system that is applied to and cured on electrical components providingelectrical, mechanical, and environmental protection.3.1.2.1 DiscussionThere are two types of electrical insulating varnish solventcontaini
7、ng and solventless. The solvent-containing varnish issolution, dispersion, or emulsion of a polymer or a mixture of polymers in a volatile, nonreactable liquid. The solventless type isa liquid resin system free of volatile, nonreactable solvents.3.1.3 varnished, adjreferring to any item on to which
8、varnish has been applied and cured.4. Significance and Use4.1 This test method is useful in determining the performance of varnishes over enamelled magnet wire when subjected to thespecified sodium chloride solution. It is useful in evaluating the resistance of varnished magnet wire to a diluted sod
9、ium chloridesolution under applied voltage.5. Apparatus5.1 Description of Electrical Apparatus :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 Varnish
10、es, Powders and Encapsulating Compounds.Current edition approved May 1, 2008May 15, 2014. Published June 2008May 2014. Originally approved in 1988. Last previous edition approved in 20032008 asD4880 03.D4880 08. DOI: 10.1520/D4880-08.10.1520/D4880-14.2 For referencedASTM standards, visit theASTM web
11、site, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indicati
12、on 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 the standard as published by ASTM is to be consi
13、dered 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 States15.1.1 The apparatus shall contain devices for limiting or interrupting the current to each sp
14、ecimen whenever a failure occurs.In particular, 7.5 W light bulbs or 110 A fuses have been used. Lighting of the bulb or “blowing” of the fuse indicates failure.5.1.2 The power supply shall provide a source of filtered 120 6 2 V dc which drops by less than 2 V when a current of 0.5A is drawn.5.1.3 A
15、 positive polarity of 120 V dc is applied to the specimens. The surrounding sodium chloride solution is at groundpotential. The ground connection, using an immersed electrode, is made using Nichrome, stainless steel, or other non-corrosivewire. Do not use iron, carbon steel, copper, or brass (see Fi
16、g. 1).5.2 An appropriate container shall be selected for the sodium chloride solution. Fit it with a cover to prevent evaporation of thesolution.6. Safety Precautions6.1 Do not use varnish at temperatures above the flash point when inadequate ventilation, and possibility of flames or sparksexist. St
17、ore varnish in sealed containers. These precautions shall also apply to the handling of the reagents and solvents called forin this test method.6.2 WarningLethal voltages are a potential hazard during the performance of this test. It is essential that the test apparatus,and all associated equipment
18、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 the completionof any test to ground any parts which were at high voltage during
19、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 performing tests safely. When making high voltage tests, particularly in compressed ga
20、s 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 possibility of such occurrences and to eliminate thepossibility of personal inj
21、ury. If the potential for fire exists, have fire suppression equipment available.7. Test Specimens Preparation7.1 Selection of Enamelled Magnet Wire The type of enamelled magnet wire used for this test shall be agreed upon betweeninterested parties. Seven of the nine unvarnished test specimens shall
22、 fail within the specified test time.7.2 Twist a section of 1.02-mm (0.0403-in.) (18-AWG) enamelled magnet wire with the appropriate number of twists andtension as described in Test Methods D1676 (see Fig. 2). Note however, that one end of the specimen is a continuous loop insteadof two loose ends.7
23、.3 Prepare 18 specimens in the manner described in 7.2.7.4 Dipping:7.4.1 Adjust the consistency of the solvent-containing varnish to give a 0.025 6 0.005-mm (0.0010 6 0.0002-in.) cured filmon each side of a 0.13-mm (.005-in.) copper strip withdrawn at a rate of approximately 100 mm/min (4 in./min).
24、Use solventlessvarnish as received.7.4.2 Dip nine twisted specimens in the varnish to be tested. After the specimens are submerged in the varnish, withdraw themat a rate of approximately 100 mm/min (4 in./min). Drain the specimens for a minimum of 10 min. Cure according to themanufacturers specifica
25、tions. Dip the specimens again in the reverse direction if a solvent-containing varnish was used. Whentesting solventless varnishes, dip test specimens only once.FIG. 1 Typical Test ApparatusD4880 1428. Procedure8.1 Perform the following for nine unvarnished specimens and nine varnished specimens.8.
26、2 Remove the enamel from the loose ends of the twisted specimens. Use these legs to make the electrical connections.8.3 For each test, prepare a solution of distilled water and sodium chloride in which the sodium chloride is at a concentrationof 3.5 6 0.1 % by weight.8.4 Set up the appropriate circu
27、it as outlined in Section 5. Connect the specimen to the electrical circuit. Then submerge thespecimens so that approximately 76 mm (3 in.) of the twisted sections of the specimens are submerged in the sodium chloridesolution.8.5 Apply 120 6 5 V dc between the specimen and the sodium chloride soluti
28、on.8.6 Check for failures daily or more often if possible and then record the total elapsed time from the application of the testvoltage to when failures are detected. The length of time of the test is 100 h unless otherwise agreed upon between the user andthe manufacturer.8.7 if seven of the nine u
29、nvarnished test specimens do not fail within the test time, repeat the test with a different enamelledmagnet wire as specified in 7.1.9. Report9.1 Report the following information:9.1.1 Identification of the varnish used,9.1.2 Identification and film build of the magnet wire used,9.1.3 The number of
30、 unvarnished specimens failed at the end of the test time and the elapsed time when each failure wasdetected,9.1.4 The number of unvarnished specimens that did not fail at the end of the test time,9.1.5 The number of varnished specimens that failed at the end of the test time and the elapsed time wh
31、en each failure wasdetected, and9.1.6 The number of varnished specimens that did not fail at the end of the test time.10. Precision and Bias10.1 PrecisionThis test method has been in use for many years, but no statement of precision has been made and no activityis planned to develop such a statement
32、.10.2 BiasThis test method has no bias because the value for salt water proofness is defined in terms of this method.11. Keywords11.1 electrical insulating ; enamelled wire; magnet wire; salt water; varnishSUMMARY OF CHANGESCommittee D09 has identified the location of selected changes to this test m
33、ethod since the last issue,D4880 03D4880 08, that may impact the use of this test method. (Approved May 1, 2008May 1, 2014)(1) Revised 7.1.(1) Revised 7.1.FIG. 2 Test SpecimenD4880 143ASTM International takes no position respecting the validity of any patent rights asserted in connection with any it
34、em 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 com
35、mittee 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 m
36、eeting 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 Drive
37、, 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/).D4880 144
