ASTM D2756-07
(Test Method)Standard Test Method for Weight Loss of Electrical Insulating Varnishes
Standard Test Method for Weight Loss of Electrical Insulating Varnishes
SIGNIFICANCE AND USE
Weight loss is useful for indicating:
5.1.1 A form of degradation at elevated temperatures in air, and
5.1.2 Evolution of volatiles that have the potential to affect other components.
SCOPE
1.1 This test method covers the measurement of the loss in weight of cured electrical insulating varnishes on exposure to elevated temperature in air.
1.2 The values stated in SI units are the standard.
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. For specific precaution statements, see Section 7.Note 1
IEC 60216 Part 2 is technically equivalent to this standard.
General Information
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D2756–07
Standard Test Method for
1
Weight Loss of Electrical Insulating Varnishes
This standard is issued under the fixed designation D2756; 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* 4. Summary of Test Method
1.1 This test method covers the measurement of the loss in 4.1 Specimens are prepared by coating glass cloth with
weight of cured electrical insulating varnishes on exposure to varnish to be tested. The specimens are aged at elevated
elevated temperature in air. temperatures and the loss in weight is determined after a
1.2 The values stated in SI units are the standard. specific time.
1.3 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
5.1 Weight loss is useful for indicating:
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 5.1.1 A form of degradation at elevated temperatures in air,
bility of regulatory limitations prior to use. For specific and
5.1.2 Evolution of volatiles that have the potential to affect
precaution statements, see Section 7.
other components.
NOTE 1—IEC 60216 Part 2 is technically equivalent to this standard.
6. Apparatus
2. Referenced Documents
6.1 Air-Circulating Oven, capable of meeting the require-
2
2.1 ASTM Standards:
ments of Specification D5423, Type II.
D115 Test Methods for Testing Solvent Containing Var-
6.2 Glass Cloth,heat-cleaned,StyleNo.116,asdescribedin
nishes Used for Electrical Insulation
Specification D2518.
D1711 Terminology Relating to Electrical Insulation
6.3 Balance, capable of weighing to nearest 0.001 g.
D1932 Test Method for Thermal Endurance of Flexible
6.4 Desiccator Jar, with a suitable desiccant.
Electrical Insulating Varnishes
D2518 Specification for Woven Glass Fabrics for Electrical
7. Safety Precautions
Insulation
7.1 Do not use varnish at temperatures above the flash point
D5423 Specification for Forced-Convection Laboratory
when inadequate ventilation and the possibility of flames or
Ovens for Evaluation of Electrical Insulation
sparksexist.Storeallvarnishes,reagentsandsolventsinsealed
2.2 IEC Standards:
containers. Apply these precautions to the handling of the
IEC 60216 Guide for the determination of thermal endur-
called for reagents and solvents.
ance properties of electrical insulating materials—Part 2:
3
Choice of test criteria
8. Sampling
8.1 Sample the varnish in accordance with Test Methods
3. Terminology
D115.
3.1 Definitions: For definitions of terms used in this test
method, refer to Terminology D1711.
9. Test Specimens
9.1 Prepare the test specimens as described in Test Method
1
This test method is under the jurisdiction of ASTM Committee D09 on D1932. Make one panel for each test temperature. Use an
Electrical and Electronic Insulating Materials and is the direct responsibility of
average of ten readings to determine the thickness of the
Subcommittee D09.01 on Electrical Insulating Varnishes, Powders and Encapsulat-
panels.
ing Compounds.
9.2 Cure the varnish in accordance with manufacturer’s
Current edition approved May 1, 2007. Published June 2007. Originally
approved in 1968. Last previous edition approved in 2002 as D2756 – 02. DOI:
requirements.
10.1520/D2756-07
9.3 Cut two specimens, 100 by 125 mm (4 by 5 in.) from
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
each panel to be used for the tests.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
9.4 Cut an uncoated piece of cloth, 100 by 125 mm (4 by 5
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
in.)
3
Available from International Electrotechnical Commission (IEC), 3 rue de
Varembé, Case postale 131, CH-1211, Geneva 20, Switzerland, http://www.iec.ch.
*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.
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D2756–07
battery clips from picking up any varnish, which could introduce an error
10. Procedure
in the measurement.
10.1 Dry two cured specimens for each test temperature and
NOTE 3—When more information is required, it is desirable to use a
one uncoated specimen for 2 h at 110 °C (230 °F). Place them
number of selected time periods (for example: 4, 24, 48, 96 h, and in some
in a desiccator and allow them to cool to room temperature.
cases, even longer periods of t
...
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