1、Designation: D4880 14Standard 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 or, in the case of revision, the year
2、 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 aspecified water solution of an insulating varnish applied
3、overenamelled magnet wire.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.3 This standard does not purport to address all of thes
4、afety 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. Specific precau-tionary statements are given in Section 6.NOTE 1There i
5、s 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 test method referto Terminology D1711.3
6、.1.2 varnish, electrical insulating, n a liquid resin systemthat is applied to and cured on electrical components providingelectrical, mechanical, and environmental protection.3.1.2.1 DiscussionThere are two types of electrical insu-lating varnish solventcontaining and solventless. Thesolvent-contai
7、ning varnish is solution, dispersion, or emulsionof a polymer or a mixture of polymers in a volatile, nonre-actable liquid. The solventless type is a liquid resin system freeof volatile, nonreactable solvents.3.1.3 varnished, adjreferring to any item on to whichvarnish has been applied and cured.4.
8、Significance and Use4.1 This test method is useful in determining the perfor-mance of varnishes over enamelled magnet wire when sub-jected to the specified sodium chloride solution. It is useful inevaluating the resistance of varnished magnet wire to a dilutedsodium chloride solution under applied v
9、oltage.5. Apparatus5.1 Description of Electrical Apparatus :5.1.1 The apparatus shall contain devices for limiting orinterrupting the current to each specimen whenever a failureoccurs. In particular, 7.5 W light bulbs or110 Afuses have beenused. Lighting of the bulb or “blowing” of the fuse indicate
10、sfailure.5.1.2 The power supply shall provide a source of filtered120 6 2 V dc which drops by less than 2 V when a current of0.5 A is drawn.5.1.3 A positive polarity of 120 V dc is applied to thespecimens. The surrounding sodium chloride solution is atground potential. The ground connection, using a
11、n immersedelectrode, is made using Nichrome, stainless steel, or othernon-corrosive wire. Do not use iron, carbon steel, copper, orbrass (see Fig. 1).5.2 An appropriate container shall be selected for thesodium chloride solution. Fit it with a cover to preventevaporation of the solution.6. Safety Pr
12、ecautions6.1 Do not use varnish at temperatures above the flash pointwhen inadequate ventilation, and possibility of flames orsparks exist. Store varnish in sealed containers. These precau-tions shall also apply to the handling of the reagents andsolvents called for in this test method.6.2 WarningLe
13、thal voltages are a potential hazard duringthe performance of this test. It is essential that the test1This test 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 Var
14、nishes, Powders and Encapsulat-ing Compounds.Current edition approved May 15, 2014. Published May 2014. Originallyapproved in 1988. Last previous edition approved in 2008 as D4880 08. DOI:10.1520/D4880-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S
15、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 194
16、28-2959. United States1apparatus, and all associated equipment electrically connectedto it, be properly designed and installed for safe operation.Solidly ground all electrically conductive parts which it ispossible for a person to contact during the test. Provide meansfor use at the completion of an
17、y test to ground any parts whichwere at high voltage during the test or have the potential foracquiring an induced charge during the test or retaining acharge even after disconnection of the voltage source. Thor-oughly instruct all operators as to the correct procedures forperforming tests safely. W
18、hen making high voltage tests,particularly in compressed gas or in oil, it is possible for theenergy released at breakdown to be sufficient to result in fire,explosion, or rupture of the test chamber. Design testequipment, test chambers, and test specimens so as to minimizethe possibility of such oc
19、currences and to eliminate thepossibility of personal injury. If the potential for fire exists,have fire suppression equipment available.7. Test Specimens Preparation7.1 Selection of Enamelled Magnet Wire The type ofenamelled magnet wire used for this test shall be agreed uponbetween interested part
20、ies. Seven of the nine unvarnished testspecimens shall 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 twistsand tension as described in Test Methods D1676 (see Fig. 2).Note however, that one end of the spec
21、imen is a continuousloop instead of two loose ends.7.3 Prepare 18 specimens in the manner described in 7.2.7.4 Dipping:7.4.1 Adjust the consistency of the solvent-containing var-nish to give a 0.025 6 0.005-mm (0.0010 6 0.0002-in.) curedfilm on each side of a 0.13-mm (.005-in.) copper stripwithdrawn
22、 at a rate of approximately 100 mm/min (4 in./min).Use solventless varnish as received.7.4.2 Dip nine twisted specimens in the varnish to be tested.After the specimens are submerged in the varnish, withdrawthem at a rate of approximately 100 mm/min (4 in./min). Drainthe specimens for a minimum of 10
23、 min. Cure according to themanufacturers specifications. Dip the specimens again in thereverse direction if a solvent-containing varnish was used.When testing solventless varnishes, dip test specimens onlyonce.8. Procedure8.1 Perform the following for nine unvarnished specimensand nine varnished spe
24、cimens.8.2 Remove the enamel from the loose ends of the twistedspecimens. Use these legs to make the electrical connections.8.3 For each test, prepare a solution of distilled water andsodium chloride in which the sodium chloride is at a concen-tration of 3.5 6 0.1 % by weight.8.4 Set up the appropri
25、ate circuit as outlined in Section 5.Connect the specimen to the electrical circuit. Then submergethe specimens so that approximately 76 mm (3 in.) of thetwisted sections of the specimens are submerged in the sodiumchloride solution.8.5 Apply 120 6 5 V dc between the specimen and thesodium chloride
26、solution.8.6 Check for failures daily or more often if possible andthen record the total elapsed time from the application of thetest voltage to when failures are detected. The length of time ofthe test is 100 h unless otherwise agreed upon between the userand the manufacturer.8.7 if seven of the ni
27、ne unvarnished test specimens do notfail within the test time, repeat the test with a differentenamelled magnet 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
28、 of unvarnished specimens failed at theend of the test time and the elapsed time when each failure wasdetected,9.1.4 The number of unvarnished specimens that did not failat the end of the test time,9.1.5 The number of varnished specimens that failed at theend of the test time and the elapsed time wh
29、en each failure wasdetected, and9.1.6 The number of varnished specimens that did not fail atthe end of the test time.10. Precision and Bias10.1 PrecisionThis test method has been in use for manyyears, but no statement of precision has been made and noactivity is planned to develop such a statement.1
30、0.2 BiasThis test method has no bias because the valuefor salt water proofness is defined in terms of this method.FIG. 1 Typical Test ApparatusFIG. 2 Test SpecimenD4880 14211. Keywords11.1 electrical insulating ; enamelled wire; magnet wire; saltwater; varnishSUMMARY OF CHANGESCommittee D09 has iden
31、tified the location of selected changes to this test method since the last issue,D4880 08, that may impact the use of this test method. (Approved May 1, 2014)(1) Revised 7.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mention
32、edin 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 committee and
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