ASTM D2519-02

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An American National Standard
Designation:D2519–02
Standard Test Method for
Bond Strength of Electrical Insulating Varnishes by the
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Helical Coil Test
This standard is issued under the fixed designation D 2519; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
3.2.1 event time—the time between initial application of a
1.1 This test method covers determination of the bond
physical or electrical stress and failure of the specimen under
strength of an electrical insulating varnish when applied to a
test.
helical coil. The helical coil can be made from bare aluminum
3.2.2 response time—the time required for an indicating or
or copper wire or from film or fiber-insulated magnet wire.
recording device to react to change in stress on a specimen
Helical coils made from bare aluminum or bare copper wire
under test.
will yield values of bond strength for the varnish when applied
3.2.3 SeeTerminology D 1711 for definitions of other terms
to bare metal conductors. The use of film or fiber-insulated
relating to electrical insulation.
magnet wire will show values for that particular combination
of insulation and varnish.
4. Summary of Test Method
1.2 The values stated in SI units are to be regarded as the
4.1 Flexural strength tests are made on varnish-treated
standard. The values given in parentheses are for information
helical coils to determine the force required to break the coil
only.
under specified conditions.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 Values obtained by flexural tests can provide informa-
priate safety and health practices and determine the applica-
tion with regard to the bond strength of the particular varnish,
bility of regulatory limitations prior to use. See Section 7.
in combination with a particular wire, when measured under
conditions described in this test method.
2. Referenced Documents
2.1 ASTM Standards:
6. Apparatus
D 115 Test Methods for Testing Solvent Containing Var-
2 6.1 Tensile Testing Machine—An adjustable-speed drive
nishes Used for Electrical Insulation
andasuitableinstrumentformeasuringforceshouldbeusedin
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D 1711 Terminology Relating to Electrical Insulation
breaking the specimen. This may be in the form of one of the
D 6054 Practice for Conditioning Electrical Insulating Ma-
generally available tensile testing machines, or may be simply
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terials for Testing
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an accurate spring gage and a separate adjustable-speed drive.
E 691 Practice for Conducting an Interlaboratory Study to
Tocovertherangeofloadstrengthvalueswhicharecommonly
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Determine the Precision of a Test Method
encountered it is recommended that a multirange tester be
used.
3. Terminology
6.1.1 It has been found that gages rated 5, 25, 150, and
3.1 Definitions:
500 N (1, 5, 30, and 100 lbf) are adequate to cover the range of
3.1.1 bond strength—a measure of the force required to
varnishes.
separate surfaces which have been bonded together.
6.2 Test Fixture—The test fixture shall consist of two
rollers, attached to a common frame, and a 90° V-block. One
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part, either the rollers or the V-block, is held stationary while
This test method is under the jurisdiction of ASTM Committee D09 on
Electrical and Electronic Insulating Materials and is the direct responsibility of
the other part is moved. There shall be no friction contact
Subcommittee D09.01 on Electrical Insulating Varnishes, Powders and Encapsulat-
which will affect this movement. The general shape and the
ing Compounds.
Current edition approved Sept. 10, 2002. Published October 2002. Originally
published as D 2519 – 66 T. Last previous edition D 2519 – 01.
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Annual Book of ASTM Standards, Vol 10.01. Spring gages from John Chattilon and Sons, 83-30 Kew Gardens Road, Kew
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Annual Book of ASTM Standards, Vol 10.02. Gardens, NY 11415 or from Hunter Spring Co., One Spring Avenue, Hatfield, PA
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Annual Book of ASTM Standards, Vol 14.02. 19440, or its equivalent, have been found satisfactory for this purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D2519–02
relative position of these parts is shown in Fig. 1. The rollers diameter mandrel. Bend the last loop on each end of the coil to
shall have a diameter of 9.5 mm (0.375 in.)
...