ASTM D1932-18
(Test Method)Standard Test Method for Thermal Endurance of Flexible Electrical Insulating Varnishes
Standard Test Method for Thermal Endurance of Flexible Electrical Insulating Varnishes
SIGNIFICANCE AND USE
5.1 A major factor affecting the long term performance of insulating materials is thermal degradation. It is possible that factors, such as moisture and vibration, will cause failures after the material has been weakened by thermal degradation.
5.2 An electrical insulating varnish is effective in protecting electrical equipment only as long as it retains its physical and electrical integrity.
5.3 The thermal degradation of the varnish results in weight loss, porosity, crazing, and generally a reduction in flexibility. Degradation of the varnish can be detected by a decrease in dielectric strength, which is therefore used as the failure criterion for this test method.
5.4 Electrical insulating varnishes undergo flexing in service due to vibration and thermal expansion. For this reason, this functional test includes flexing and elongation of the insulation. The electrodes used in this test method are designed to elongate the outer surface of the specimen 2 % with respect to the neutral axis of the base fiber while being tested for dielectric breakdown.
SCOPE
1.1 This test method covers the determination of the relative thermal endurance of flexible electrical insulating varnishes by determining the time necessary at elevated temperatures to decrease the dielectric breakdown of the varnish to an arbitrarily selected value when applied to a standard glass fiber fabric.
1.2 This test method does not apply to varnishes that lose a high percentage of their dielectric breakdown voltage when flexed before elevated temperature exposure as prescribed in the screening test (Section 9). Examples of such varnishes are those used for high speed armatures and laminated structures. Also, this test method is not applicable to varnishes which distort sufficiently during thermal elevated temperature exposure so that they cannot be tested using the curved electrode assembly.
1.3 Thermal endurance is expressed in terms of a temperature index.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
Note 1: There is no equivalent IEC or ISO standard.
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Buy Standard
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: D1932 − 18
Standard Test Method for
Thermal Endurance of Flexible Electrical Insulating
1
Varnishes
This standard is issued under the fixed designation D1932; 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* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 Thistestmethodcoversthedeterminationoftherelative
thermal endurance of flexible electrical insulating varnishes by
2. Referenced Documents
determining the time necessary at elevated temperatures to
2
decrease the dielectric breakdown of the varnish to an arbi- 2.1 ASTM Standards:
D149 Test Method for Dielectric Breakdown Voltage and
trarily selected value when applied to a standard glass fiber
fabric. DielectricStrengthofSolidElectricalInsulatingMaterials
at Commercial Power Frequencies
1.2 This test method does not apply to varnishes that lose a
D374/D374M Test Methods for Thickness of Solid Electri-
high percentage of their dielectric breakdown voltage when
cal Insulation
flexed before elevated temperature exposure as prescribed in
D580/D580M Specification for Greige Woven Glass Tapes
the screening test (Section 9). Examples of such varnishes are
and Webbings
those used for high speed armatures and laminated structures.
D618 Practice for Conditioning Plastics for Testing
Also, this test method is not applicable to varnishes which
D1346 Test Method for Testing Electrical Insulating Var-
distort sufficiently during thermal elevated temperature expo-
3
nishes for 180 C and Above (Withdrawn 1986)
sure so that they cannot be tested using the curved electrode
D1711 Terminology Relating to Electrical Insulation
assembly.
D2307 Test Method for Thermal Endurance of Film-
1.3 Thermal endurance is expressed in terms of a tempera-
Insulated Round Magnet Wire
ture index.
D2518 Specification for Woven Glass Fabrics for Electrical
3
Insulation (Withdrawn 2013)
1.4 The values stated in SI units are to be regarded as
D5423 Specification for Forced-Convection Laboratory Ov-
standard. No other units of measurement are included in this
ens for Evaluation of Electrical Insulation
standard.
2.2 IEC Publications:
NOTE 1—There is no equivalent IEC or ISO standard.
IEC 60216 Guide for the Determination of Thermal Endur-
4
1.5 This standard does not purport to address all of the
ance Properties of Electrical Insulating Materials (Part 1)
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety, health, and environmental practices and deter-
3.1 Definitions:
mine the applicability of regulatory limitations prior to use.
3.1.1 temperature index (TI), n—a number which permits
For specific hazard statements, see Section 7.
comparison of the temperature/time characteristics of an elec-
1.6 This international standard was developed in accor-
trical insulating material, or a simple combination of materials,
dance with internationally recognized principles on standard-
based on the temperature in degrees Celsius which is obtained
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
2
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
1
This test method is under the jurisdiction of ASTM Committee D09 on Standards volume information, refer to the standard’s Document Summary page on
Electrical and Electronic Insulating Materials and is the direct responsibility of the ASTM website.
3
Subcommittee D09.01 on Electrical Insulating Products. The last approved version of this historical standard is referenced on
Current edition approved Nov. 1, 2018. Published November 2018. Originally www.astm.org.
4
approved in 1967. Last previous edition approved in 2013 as D1932 – 13. DOI: Available from American National Standards Institute, 25 West 43rd St., 4th
10.1520/D1932-18. Floor, New York, NY 10036.
*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
1
---------------------- Page: 1 ----------------------
D1932 − 18
by extrapolating the Arrhenius plot of endpoint time versus 5. Significance and Use
temperature to a specified time, usually 20 000 h.
5.1 A major factor affecting the long term performance of
3.1.2 thermal endurance graph, n—an Arrhenius plot.
insul
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D1932 − 13 D1932 − 18
Standard Test Method for
Thermal Endurance of Flexible Electrical Insulating
1
Varnishes
This standard is issued under the fixed designation D1932; 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*
1.1 This test method covers the determination of the relative thermal endurance of flexible electrical insulating varnishes by
determining the time necessary at elevated temperatures to decrease the dielectric breakdown of the varnish to an arbitrarily
selected value when applied to a standard glass fiber fabric.
1.2 This test method does not apply to varnishes that lose a high percentage of their dielectric breakdown voltage when flexed
before elevated temperature exposure as prescribed in the screening test (Section 9). Examples of such varnishes are those used
for high speed armatures and laminated structures. Also, this test method is not applicable to varnishes which distort sufficiently
during thermal elevated temperature exposure so that they cannot be tested using the curved electrode assembly.
1.3 Thermal endurance is expressed in terms of a temperature index.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
NOTE 1—There is no equivalent IEC or ISO standard.
1.5 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at
Commercial Power Frequencies
D374D374/D374M Test Methods for Thickness of Solid Electrical Insulation (Metric) D0374_D0374M
D580D580/D580M Specification for Greige Woven Glass Tapes and Webbings
D618 Practice for Conditioning Plastics for Testing
3
D1346 Test Method for Testing Electrical Insulating Varnishes for 180 C and Above (Withdrawn 1986)
D1711 Terminology Relating to Electrical Insulation
D2307 Test Method for Thermal Endurance of Film-Insulated Round Magnet Wire
3
D2518 Specification for Woven Glass Fabrics for Electrical Insulation (Withdrawn 2013)
D5423 Specification for Forced-Convection Laboratory Ovens for Evaluation of Electrical Insulation
3
D6054 Practice for Conditioning Electrical Insulating Materials for Testing (Withdrawn 2012)
4
2.2 IEEE Publications:
IEEE No. 101A Guide for the Statistical Analysis of Thermal Life Test Data (including Appendix A)
1
This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of Subcommittee
D09.01 on Electrical Insulating Varnishes, Powders and Encapsulating CompoundsProducts.
Current edition approved April 1, 2013Nov. 1, 2018. Published April 2013November 2018. Originally approved in 1967. Last previous edition approved in 20092013 as
D1932 – 04 (2009).D1932 – 13. DOI: 10.1520/D1932-13.10.1520/D1932-18.
2
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
The last approved version of this historical standard is referenced on www.astm.org.
*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
1
---------------------- Page: 1 ----------------------
D1932 − 18
2.2 IEC Publications:
4
IEC 60216 Guide for the Determination of Thermal Endurance Properties of Electrical Insulating M
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.