1、Designation: D4882 05 (Reapproved 2012)D4882 17Standard Test Method forBond Strength of Electrical Insulating Varnishes by theTwisted-Coil Test1This standard is issued under the fixed designation D4882; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e 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 the bond strength of an electrical
3、 insulating varnish when applied to a twistedcoil of film-insulated magnet wire. The use of a particular type of film-insulated wire will show the values for that combinationof film coating and varnish.1.2 The values stated in inch-pound units are the standard. The values given in parentheses are fo
4、r information only.NOTE 1Although this standard and Method C of IEC 61033 differ in approach or detail, data obtained using either are technically equivalent.1.3 This standard does not purport to address all, if any, all of the safety concerns, if any, associated with its use. It is theresponsibilit
5、y of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices anddetermine the applicability of regulatory limitations prior to use. A specific precautionary statement is given in Section 7.1.4 This international standard was developed in accordance
6、 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 Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standar
7、ds:2D115 Test Methods for Testing Solvent Containing Varnishes Used for Electrical InsulationD1711 Terminology Relating to Electrical InsulationD2519 Test Method for Bond Strength of Electrical Insulating Varnishes by the Helical Coil TestD6054 Practice for Conditioning Electrical Insulating Materia
8、ls for Testing (Withdrawn 2012)32.2 IEC Standard:IEC 61033 Test Methods for the Determination of Bond Strength of Impregnating Agents to an Enamelled Wire Substrate43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 bond strength, na measure of the force required to separate surf
9、aces which have been bonded together.3.2 Refer to Terminology D1711 for definitions of other terms.4. Summary of Test Method4.1 Flexural strength tests are made on twisted coils to determine the force required to break the coils under specific conditions.5. Significance and Use5.1 Values obtained by
10、 flexural test can provide provides information with regard to the bond strength of the particular varnishin combination with a particular type of magnet wire, when measured under conditions described in this test method.1 This test method is under the jurisdiction of ASTM Committee D09 on Electrica
11、l and Electronic Insulating Materials and is the direct responsibility of SubcommitteeD09.01 on Electrical Insulating Varnishes, Powders and Encapsulating CompoundsProducts.Current edition approved Jan. 1, 2012Nov. 1, 2017. Published January 2012November 2017. Originally approved in 1988. Last previ
12、ous edition approved in 20052012as D4882 05.D4882 05 (2012). DOI: 10.1520/D4882-05R12.10.1520/D4882-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards
13、Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from American National Standards Institute, 25 W. 43rd St., 4th Floor, New York, NY 10036.This document is not an ASTM standard and is intended only to provide
14、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 the stan
15、dard 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. Apparatus6.1 Coil winder as shown in Fig. 1 and Fi
16、g. 2.6.2 Coil Twister as shown in Fig. 3.6.3 Test apparatus as described in Test Method D2519.7. Safety Precautions7.1 It is unsafe to use varnish at temperatures above the flash point without adequate ventilation, especially if the possibilityexists that flames or sparks are present. Store varnish
17、in sealed containers.8. Test Specimen Preparation8.1 The test specimen is a wound coil made from film-insulated magnet wire, 28 AWG (0.320 mm). The coil shall be made bymeans of suitable winding equipment as shown in Fig. 1. To prevent opening of the coil after removal from the winding equipment,eac
18、h end of the magnet wire, or short pieces of film-insulated wire, may be are wrapped around the coil two or three times. Forthis purpose the winding equipment is provided with appropriate notches as shown in Fig. 2. For winding the coil the followingdimensions apply:Winding diameter 2.25 0.05 in. (5
19、7 1 mm)Winding diameter 2.25 0.05 in. (57.2 1 mm)Width of slot .25 0.05 in. (6 1 mm)Width of slot .25 0.05 in. (6.4 1 mm)Number of turns 100 (See Note 2)Nominal wire diameter 28 AWG (0.320 mm)NOTE 2Instead of 100 turns of a single wire, 50 turns of two parallel wires may be used are allowable to pro
20、vide a bifilar winding.8.1.1 After the coil has been wound, remove it from the winding equipment and stretch into an oval shape as shown in Fig. 4.Twist the coil two full turns around its longitudinal axis by means of a twisting device as shown in Fig. 3. The twisted coil formedis about 0.28 in. (7(
21、7.1 mm) in diameter and 3.25 to 3.5 in. (85(82.6 to 90 mm) 88.9 mm) in length and serves as a substrate forthe varnish.8.2 The type of magnet wire and test conditions shall be mutually agreed upon between all involved parties.8.3 Prepare six or more specimens for each condition to be investigated.8.
22、4 For solvent-containing varnishes, adjust the viscosity of the varnish by trial, to produce a dry film build of 0.0017 to 0.0021in. (.043 to .053 mm) on a double-coated copper panel coated in accordance with Test Methods D115.8.5 Do not adjust solventless varnishes.FIG. 1 Coil WinderD4882 1728.6 At
23、tach several twisted coils to a rack and immerse vertically in the varnish until bubbling stops. Withdraw them at 4 6 0.2in./min (100 6 5 mm/min) and allow them to drain horizontally for solventless varnishes 10 to 12 min at standard laboratoryatmosphere in accordance with Practice D6054. For solven
24、t-containing varnishes drain vertically 10 to 12 min at standardlaboratory atmosphere in accordance with Practice D6054. Place the coils in an oven in the same position as drained. Cure at thetemperature and for the time recommended by the manufacturer. Reverse dip the coils following the preceding
25、steps if testing asolvent-containing varnish.8.7 When testing solventless varnishes the twisted coils are single dipped.9. Procedure9.1 Follow the procedure as required in Test Method D2519.10. Report10.1 Report the data as required in Test Method D2519.11. Precision and Bias511.1 PrecisionData from
26、 an interlaboratory study of this test method are as follows:Data from six laboratories, 10 individual values from each laboratory per condition tested.Tested at 25 CMean 51 lbf (227 N)Standard Deviation 8.1 lbf (36 N)95 % Confidence level 15.9 lbf (71 N)Tested at 150 CMean 31 lbf (138 N)Standard De
27、viation 4.4 lbf (20 N)95 % Confidence level 8.6 lbf (38 N)11.2 BiasThis test method has no bias because the value for bond strength of electrical insulating varnishes by the twisted coiltest is defined solely in terms of this test method.12. Keywords12.1 bond strength; electrical insulating; magnet
28、wire; twisted coil; varnish5 Supporting data are available from ASTM Headquarters. Request RR:D-9-1027.FIG. 2 Coil Winder, Front ViewD4882 173SUMMARY OF CHANGESCommittee D09 has identified the location of selected changes to this standard since the last issue (D4882 05(2012) that may impact the use
29、of this standard. (Approved Nov. 1, 2017.)(1) Removed non-mandatory language from 5.1 and 8.1.(2) Updated unit conversions in 8.1 and 8.1.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this
30、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 must be reviewed every five years
31、 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 meeting of theresponsible technical committee
32、, 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, PO Box C700, West Conshohocken, PA 19428-2
33、959,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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 3 Coil TwisterFIG. 4 Oval-Shaped CoilD4882 174
