ASTM D2756-85(1998)

Standard Test Method for Weight Loss of Electrical Insulating Varnishes

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 to be regarded as 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 5.

General Information

• Status: Historical
• Publication Date: 09-Nov-1998
• ICS: 29.035.60 - Varnished fabrics
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.01 - Electrical Insulating Products

Relations

• Replaced By: ASTM D2756-02 - Standard Test Method for Weight Loss of Electrical Insulating Varnishes
• Effective Date: 10-Sep-2002

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NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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: D 2756 – 85 (Reapproved 1998)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Weight Loss of Electrical Insulating Varnishes
This standard is issued under the fixed designation D 2756; 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.
1. Scope 5.1.2 Evolution of volatiles which may affect other compo-
nents.
1.1 This test method covers the measurement of the loss in
weight of cured electrical insulating varnishes on exposure to
6. Apparatus
elevated temperature in air.
6.1 Air-Circulating Oven, capable of meeting the require-
1.2 The values stated in SI units are the standard.
ments of Specification D 5423, Type II.
1.3 This standard does not purport to address all of the
6.2 Glass Cloth, heat-cleaned, Style No. 116, as described in
safety concerns, if any, associated with its use. It is the
Specification D 2518.
responsibility of the user of this standard to establish appro-
6.3 Balance, capable of weighing to nearest 0.001 g.
priate safety and health practices and determine the applica-
6.4 Desiccator Jar, with a suitable desiccant.
bility of regulatory limitations prior to use. For specific
precaution statements, see Section 7.
7. Safety Precautions
2. Referenced Documents 7.1 Varnish should not be used at temperatures above the
flash point when inadequate ventilation and the possibility of
2.1 ASTM Standards:
flames or sparks exist. Varnish should be stored in sealed
D 115 Test Methods for Testing Solvent Containing Var-
2 containers. The precautions shall also apply to the handling of
nishes Used for Electrical Insulation
2 the called for reagents and solvents.
D 1711 Terminology Relating to Electrical Insulation
D 1932 Test Method for Thermal Endurance of Flexible
8. Sampling
Electrical Insulating Varnishes
8.1 Sample the varnish in accordance with Test Methods
D 2518 Specification for Woven Glass Fabrics for Electrical
3 D 115.
Insulation
D 5423 Specification for Forced-Convection Laboratory
9. Test Specimens
Ovens for Evaluation of Electrical Insulation
9.1 Prepare the test specimens as described in Test Method
D 1932. Make one panel for each test temperature. Use an
3. Terminology
average of ten readings to determine the thickness of the
3.1 Definitions: For definitions of terms used in this test
panels.
method, refer to Terminology D 1711.
9.2 Cure the varnish in accordance with manufacturer’s
4. Summary of Test Method requirements.
9.3 Cut two specimens, 100 by 125 mm (4 by 5 in.) from
4.1 Specimens are prepared by coating glass cloth with
each panel to be used for the tests.
varnish to be tested. The specimens are aged at elevated
9.4 Cut an uncoated piece of cloth, 100 by 125 mm (4 by 5
temperatures and the loss in weight is determined after a
in.)
specific time.
10. Procedure
5. Significance and Use
10.1 Dry two cured specimens for each test temperature and
5.1 Weight loss is useful for indicating:
one uncoated specimen for2hat110°C (230°F). Place them in
5.1.1 A form of degradation at elevated temperatures in air,
a desiccator and allow them to cool to room temperature.
and
Weigh each specimen to the nearest 0.001 g. The weight of the
coated specimen will be the initial weight.
This test method is under the jurisdiction of ASTM Committee D-9 on
10.2 Subtract the weight of the uncoated specimen from the
Electrical and Electronic Insulating Materials and is the direct responsibility of
weight of each coated specimen. This is the initial weight of t
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