ASTM D2756-07(2012)
(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:
A form of degradation at elevated temperatures in air, and
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.
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. 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation: D2756 − 07 (Reapproved 2012)
Standard Test Method for
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* 3. Terminology
1.1 This test method covers the measurement of the loss in 3.1 Definitions: For definitions of terms used in this test
weight of cured electrical insulating varnishes on exposure to method, refer to Terminology D1711.
elevated temperature in air.
4. Summary of Test Method
1.2 The values stated in SI units are the standard.
4.1 Specimens are prepared by coating glass cloth with
1.3 This standard does not purport to address all of the
varnish to be tested. The specimens are aged at elevated
safety concerns, if any, associated with its use. It is the
temperatures and the loss in weight is determined after a
responsibility of the user of this standard to establish appro-
specific time.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific
5. Significance and Use
precaution statements, see Section 7.
5.1 Weight loss is useful for indicating:
NOTE 1—IEC 60216 Part 2 is technically equivalent to this standard.
5.1.1 Aform of degradation at elevated temperatures in air,
and
2. Referenced Documents
5.1.2 Evolution of volatiles that have the potential to affect
2.1 ASTM Standards:
other components.
D115 Test Methods for Testing Solvent Containing Var-
nishes Used for Electrical Insulation
6. Apparatus
D1711 Terminology Relating to Electrical Insulation
6.1 Air-Circulating Oven, capable of meeting the require-
D1932 Test Method for Thermal Endurance of Flexible
ments of Specification D5423, Type II.
Electrical Insulating Varnishes
D2518 Specification for Woven Glass Fabrics for Electrical
6.2 Glass Cloth,heat-cleaned,StyleNo.116,asdescribedin
Insulation (Withdrawn 2013)
Specification D2518.
D5423 Specification for Forced-Convection Laboratory Ov-
6.3 Balance, capable of weighing to nearest 0.001 g.
ens for Evaluation of Electrical Insulation
6.4 Desiccator Jar, with a suitable desiccant.
2.2 IEC Standards:
IEC 60216 Guide for the determination of thermal endur-
7. Safety Precautions
ance properties of electrical insulating materials—Part 2:
Choice of test criteria 7.1 Do not use varnish at temperatures above the flash point
when inadequate ventilation and the possibility of flames or
sparksexist.Storeallvarnishes,reagentsandsolventsinsealed
This test method is under the jurisdiction of ASTM Committee D09 on
containers. Apply these precautions to the handling of the
Electrical and Electronic Insulating Materials and is the direct responsibility of
called for reagents and solvents.
Subcommittee D09.01 on Electrical Insulating Varnishes, Powders and Encapsulat-
ing Compounds.
Current edition approved April 1, 2012. Published April 2012. Originally 8. Sampling
approved in 1968. Last previous edition approved in 2007 as D2756 – 07. DOI:
8.1 Sample the varnish in accordance with Test Methods
10.1520/D2756-07R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or D115.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
9. Test Specimens
the ASTM website.
The last approved version of this historical standard is referenced on
9.1 Prepare the test specimens as described in Test Method
www.astm.org.
D1932. Make one panel for each test temperature. Use an
Available from International Electrotechnical Commission (IEC), 3 rue de
average of ten readings to determine the thickness of the
Varembé, Case postale 131, CH-1211, Geneva 20, Switzerland, http://www.iec.ch.
panels.
*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
D2756 − 07 (2012)
TABLE 1 Round-Robin Test Results
9.2 Cure the varnish in accordance with manufacturer’s
requirements. Interlaboratory Standard
Hours at 200 °C Avg. Weight Loss, %
Deviation
9.3 Cut two specimens
...
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