ASTM D2519-07(2012)
(Test Method)Standard Test Method for Bond Strength of Electrical Insulating Varnishes by the Helical Coil Test
Standard Test Method for Bond Strength of Electrical Insulating Varnishes by the Helical Coil Test
SIGNIFICANCE AND USE
Values obtained by flexural tests can provide information with regard to the bond strength of the particular varnish, in combination with a particular wire, when measured under conditions described in this test method.
SCOPE
1.1 This test method covers determination of the bond strength of an electrical insulating varnish when applied to a helical coil. The helical coil can be made from bare aluminum or copper wire or from film or fiber-insulated magnet wire. Helical coils made from bare aluminum or bare copper wire will yield values of bond strength for the varnish when applied to bare metal conductors. The use of film or fiber-insulated magnet wire will show values for that particular combination of insulation and varnish.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all 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 use. See Section 7.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D2519 − 07 (Reapproved 2012)
Standard Test Method for
Bond Strength of Electrical Insulating Varnishes by the
Helical Coil Test
This standard is issued under the fixed designation D2519; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 3. Terminology
1.1 This test method covers determination of the bond 3.1 Definitions:
strength of an electrical insulating varnish when applied to a 3.1.1 For definitions of other terms relating to electrical
helical coil. The helical coil can be made from bare aluminum insulation, see Terminology D1711.
or copper wire or from film or fiber-insulated magnet wire. 3.1.2 bond strength—a measure of the force required to
Helical coils made from bare aluminum or bare copper wire separate surfaces which have been bonded together.
will yield values of bond strength for the varnish when applied
3.2 Definitions of Terms Specific to This Standard:
to bare metal conductors. The use of film or fiber-insulated
3.2.1 event time—the time between initial application of a
magnet wire will show values for that particular combination
physical or electrical stress and failure of the specimen under
of insulation and varnish.
test.
1.2 The values stated in SI units are to be regarded as the
3.2.2 response time—the time required for an indicating or
standard. The values given in parentheses are for information
recording device to react to change in stress on a specimen
only.
under test.
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 Flexural strength tests are made on varnish-treated
priate safety and health practices and determine the applica-
helical coils to determine the force required to break the coil
bility of regulatory limitations prior to use. See Section 7.
under specified conditions.
5. Significance and Use
2. Referenced Documents
2.1 ASTM Standards: 5.1 Values obtained by flexural tests can provide informa-
tion with regard to the bond strength of the particular varnish,
D115 Test Methods for Testing Solvent Containing Var-
nishes Used for Electrical Insulation in combination with a particular wire, when measured under
conditions described in this test method.
D1711 Terminology Relating to Electrical Insulation
D6054 Practice for Conditioning Electrical Insulating Mate-
6. Apparatus
rials for Testing (Withdrawn 2012)
E691 Practice for Conducting an Interlaboratory Study to
6.1 Tensile Testing Machine—Use an adjustable-speed drive
Determine the Precision of a Test Method and a suitable instrument for measuring force to break the
specimen. Available tensile testing machines or an accurate
springgaugeandaseparateadjustable-speeddrivearesuitable.
This test method is under the jurisdiction of ASTM Committee D09 on
Tocovertherangeofloadstrengthvalueswhicharecommonly
Electrical and Electronic Insulating Materials and is the direct responsibility of
encountered it is recommended that a multirange tester be
Subcommittee D09.01 on Electrical Insulating Varnishes, Powders and Encapsulat-
used.
ing Compounds.
6.1.1 It has been found that gages rated 5, 25, 150, and
Current edition approved April 1, 2012. Published April 2012. Originally
approved in 1966. Last previous edition approved in 2007 as D2519 – 07. DOI:
500 N (1, 5, 30, and 100 lbf) are adequate to cover the range of
10.1520/D2519-07R12.
varnishes.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.2 Test Fixture—The test fixture consists of two rollers,
Standards volume information, refer to the standard’s Document Summary page on
attached to a common frame, and a 90° V-block. One part,
the ASTM website.
either the rollers or the V-block, is held stationary while the
The last approved version of this historical standard is referenced on
www.astm.org. other part is moved. No friction contact which will affect this
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2519 − 07 (2012)
movement is allowed. The general shape and the relative 8.1.1 Bare aluminum wire,
position of these parts are shown in Fig. 1. The rollers have a 8.1.2 Bare copper wire,
diameter of 9.5 mm (0.375 in.) at the center and are parallel
8.1.3 Film-coated magnet wire, or
having a center-to-center distance of 44.5 mm (1.75 in.). The
8.1.4 Fiber-insulated magnet wire.
90° V-block has a radius at the apex of 0.8 mm (0.03 in.).
NOTE 1—A practical method of winding a tight helical coil is to guide
6.3 Test Fixture Enclosure—For tests at other than room
the wire from the rotating reel between folds of a clean cloth onto the
temperature,useaninsulatedheat-resistantenclosure,designed rotatingmandrelusingmoderatehandtension.Maintainatrailingangleof
1 to 5° from a perpendicular to the mandrel. When the wire is cut, the coil
tofitaroundthetestfixtureandconnectedtothetensiontesting
must be restrained to avoid rapid spring back.
machine. This enclosure permits a frictionless connection
8.2 Prepare six or more specimens for each condition to be
between the test fixture and the instrument that measures the
investigated.
breaking force. The enclosure is designed with a suitable
location for holding six or more specimens. It is heated or
8.3 Adjust the viscosity of the varnish to be tested, by trial,
cooledbyaseparatesourceofuniformlycirculatinghotorcold
to produce a dry film build of 0.043 to 0.053 mm (0.0017 to
air. The temperature control system is capable of returning the
0.0021 in.) on a metal panel double coated in accordance with
test specimens and the chamber to the test temperature in less
Test Methods D115.
than 10 min. A thermostatic
...
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