ASTM D4882-05

Standard Test Method for Bond Strength of Electrical Insulating Varnishes by the Twisted-Coil Test

SIGNIFICANCE AND USE
Values obtained by flexural test can provide information with regard to the bond strength of the particular varnish in combination with a particular type of magnet wire, when measured under conditions described in this test method.
SCOPE
1.1 This test method covers the determination of the bond strength of an electrical insulating varnish when applied to a twisted coil of film-insulated magnet wire. The use of a particular type of film-insulated wire will show the values for that combination of film coating and varnish.
1.2 This standard does not purport to address all, if any, of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to useA specific precautionary statement is given in Section .
1.3 The values stated in inch-pound units are the standard. The values given in parentheses are for information only. Note 1 Although this standard and Method C of IEC 61033 differ in approach or detail, data obtained using either are technically equivalent.

General Information

• Status: Historical
• Publication Date: 31-Aug-2005
• ICS: 29.035.60 - Varnished fabrics
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.01 - Electrical Insulating Products

Relations

• Replaces: ASTM D4882-01 - Standard Test Method for Bond Strength of Electrical Insulating Varnishes by the Twisted-Coil Test
• Effective Date: 01-Sep-2005
• Replaced By: ASTM D4882-05(2012) - Standard Test Method for Bond Strength of Electrical Insulating Varnishes by the Twisted-Coil Test
• Effective Date: 01-Jan-2012
• Referred By: ASTM D1711-22 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Sep-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
Designation:D4882–05
Standard Test Method for
Bond Strength of Electrical Insulating Varnishes by the
1
Twisted-Coil Test
This standard is issued under the fixed designation D4882; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers the determination of the bond 3.1 Definitions of Terms Specific to This Standard:
strength of an electrical insulating varnish when applied to a 3.1.1 bond strength, n—a measure of the force required to
twisted coil of film-insulated magnet wire. The use of a separate surfaces which have been bonded together.
particular type of film-insulated wire will show the values for 3.2 Refer to Terminology D1711 for definitions of other
that combination of film coating and varnish. terms.
1.2 This standard does not purport to address all, if any, of
4. Summary of Test Method
the safety concerns, if any, associated with its use. It is the
4.1 Flexural strength tests are made on twisted coils to
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- determine the force required to break the coils under specific
conditions.
bility of regulatory limitations prior to use. A specific precau-
tionary statement is given in Section 7.
5. Significance and Use
1.3 The values stated in inch-pound units are the standard.
5.1 Values obtained by flexural test can provide information
The values given in parentheses are for information only.
with regard to the bond strength of the particular varnish in
NOTE 1—Although this standard and Method C of IEC 61033 differ in
combination with a particular type of magnet wire, when
approach or detail, data obtained using either are technically equivalent.
measured under conditions described in this test method.
2. Referenced Documents
6. Apparatus
2
2.1 ASTM Standards:
6.1 Coil winder as shown in Fig. 1 and Fig. 2.
D115 Test Methods for Testing Solvent Containing Var-
6.2 Coil Twister as shown in Fig. 3.
nishes Used for Electrical Insulation
6.3 Test apparatus as described in Test Method D2519.
D1711 Terminology Relating to Electrical Insulation
D2519 Test Method for Bond Strength of Electrical Insu-
7. Safety Precautions
lating Varnishes by the Helical Coil Test
7.1 It is unsafe to use varnish at temperatures above the
D6054 Practice for Conditioning Electrical Insulating Ma-
flash point without adequate ventilation, especially if the
terials for Testing
possibility exists that flames or sparks are present. Store
2.2 IEC Standard:
varnish in sealed containers.
IEC 61033 Test Methods for the Determination of Bond
Strength of Impregnating Agents to an Enamelled Wire
8. Test Specimen Preparation
3
Substrate
8.1 The test specimen is a wound coil made from film-
insulated magnet wire, 28AWG (0.320 mm). The coil shall be
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD9onElectrical
madebymeansofsuitablewindingequipmentasshowninFig.
and Electronic Insulating Materials and is the direct responsibility of Subcommittee
1. To prevent opening of the coil after removal from the
D09.01onElectricalInsulatingVarnishes,Powders,andEncapsulatingCompounds.
winding equipment, each end of the magnet wire, or short
Current edition approved Sept. 1, 2005. Published September 2005. Originally
pieces of film-insulated wire, may be wrapped around the coil
approved in 1988. Last previous edition approved in 2001 as D4882 – 01. DOI:
10.1520/D4882-05.
two or three times. For this purpose the winding equipment is
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
provided with appropriate notches as shown in Fig. 2. For
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
winding the coil the following dimensions apply:
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3
Available from American National Standards Institute, 25 W. 43rd St., 4th
Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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D4882–05
coilformedisabout0.28in.(7mm)indiameterand3.25to3.5
in. (85 to 90 mm) in length and serves as a substrate for the
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.
8.4 For solvent-containing varnishes, adjust the viscosity of
the varnish by trial, to produce a dry film bui
...