ASTM D1830-17(2024)
(Test Method)Standard Test Method for Thermal Endurance of Flexible Sheet Materials Used for Electrical Insulation by the Curved Electrode Method
Standard Test Method for Thermal Endurance of Flexible Sheet Materials Used for Electrical Insulation by the Curved Electrode Method
SIGNIFICANCE AND USE
5.1 A major factor affecting the life of insulating materials is thermal degradation. Other factors, such as moisture and vibration, are able to cause failures after the material has been weakened by thermal degradation.
5.2 Electrical insulation is effective in electrical equipment only as long as it retains its physical and electrical integrity. Thermal degradation is able to be characterized by weight change, porosity, crazing, and generally a reduction in flexibility, and is usually accompanied by an ultimate reduction in dielectric breakdown voltage.
SCOPE
1.1 This test method provides a procedure for evaluating thermal endurance of flexible sheet materials by determining dielectric breakdown voltage at room temperature after aging in air at selected elevated temperatures. Thermal endurance is expressed in terms of a temperature index.
1.2 This test method is applicable to such solid electrical insulating materials as coated fabrics, dielectric films, composite laminates, and other materials where retention of flexibility after heat aging is of major importance (see Note 4).
1.3 This test method is not intended for the evaluation of rigid laminate materials nor for the determination of thermal endurance of those materials which are not expected or required to retain flexibility in actual service.
1.4 The values stated in acceptable metric units are to be regarded as the standard. The values in parentheses are for information only.
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 a specific hazard statement, see 10.1.
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
Standards Content (Sample)
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.
Designation: D1830 − 17 (Reapproved 2024)
Standard Test Method for
Thermal Endurance of Flexible Sheet Materials Used for
Electrical Insulation by the Curved Electrode Method
This standard is issued under the fixed designation D1830; 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 2. Referenced Documents
1.1 This test method provides a procedure for evaluating 2.1 ASTM Standards:
thermal endurance of flexible sheet materials by determining D149 Test Method for Dielectric Breakdown Voltage and
dielectric breakdown voltage at room temperature after aging Dielectric Strength of Solid Electrical Insulating Materials
in air at selected elevated temperatures. Thermal endurance is at Commercial Power Frequencies
expressed in terms of a temperature index. D374 Test Methods for Thickness of Solid Electrical Insu-
lation (Metric) D0374_D0374M
1.2 This test method is applicable to such solid electrical
D5423 Specification for Forced-Convection Laboratory Ov-
insulating materials as coated fabrics, dielectric films, compos-
ens for Evaluation of Electrical Insulation
ite laminates, and other materials where retention of flexibility
2.2 Institute of Electrical and Electronics Engineers Publi-
after heat aging is of major importance (see Note 4).
cations:
1.3 This test method is not intended for the evaluation of
IEEE No. 1 General Principles for Temperature Limits in the
rigid laminate materials nor for the determination of thermal
Rating of Electrical Equipment
endurance of those materials which are not expected or
IEEE No. 101A Guide for the Statistical Analysis of Ther-
required to retain flexibility in actual service.
mal Life Test Data (including Appendix A)
1.4 The values stated in acceptable metric units are to be
2.3 IEC Publications:
regarded as the standard. The values in parentheses are for
IEC 216 Guide for the Determination of Thermal Endurance
information only.
Properties of Electrical Insulating Materials (Parts 1 and
2)
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
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, n—a number which permits com-
For a specific hazard statement, see 10.1.
parison of the temperature/time characteristics of an electrical
1.6 This international standard was developed in accor-
insulating material, or a simple combination of materials, based
dance with internationally recognized principles on standard-
on the temperature in degrees Celsius which is obtained by
ization established in the Decision on Principles for the
extrapolating the Arrhenius plot of life versus temperature to a
Development of International Standards, Guides and Recom-
specified time, usually 20 000 h.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
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
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.
Subcommittee D09.01 on Electrical Insulating Products Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),
Current edition approved March 1, 2024. Published March 2024. Originally 445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331.
approved in 1961. Last previous edition approved in 2017 as D1830 – 17. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/D1830-17R24. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1830 − 17 (2024)
3.1.2 thermal life, n—the time necessary for a specific vibration, are able to cause failures after the material has been
property of a material, or simple combination of materials, to weakened by thermal degradation.
degrade to a defined end point when aged at a specific
5.2 Electrical insulation is effective in electrical equipment
temperature.
only as long as it retains its physical and electrical integrity.
3.1.3 thermal life curve, n—a graphical representation of
Thermal degradation is able to be characterized by weight
thermal life at a specified aging temperature in which the value
change, porosity, crazing, and generally a reduction in
of a property of a material, or a simple combination of
flexibility, and is usually accompanied by an ultimate reduction
materials, is measured at room temperature and the values
in dielectric breakdown voltage.
plotted as a function of time.
6. Apparatus
3.2 Definitions of Terms Specific to This Standard:
3.2.1 thermal endurance graph—a straight-line plot of the
6.1 Electrode Test Fixture—The fixture shall be in accor-
logarithm of thermal life in hours versus the reciprocal of the
dance with the dimensions shown in Fig. 1 and Fig. 2.
absolute aging temperature in kelvins (also known as the
Electrodes shall be of polished brass, with the upper electrode
Arrhenius plot).
having a mass of 1.8 kg 6 0.05 kg (4.0 lb 6 0.1 lb).
4. Summary of Test Method
6.2 Dielectric Breakdown Test Set—The set shall meet the
requirements of Test Method D149.
4.1 Specimens are aged in air at a minimum of three
temperatures above the expected use temperature of the mate-
6.3 Ovens—Ovens shall meet the requirements of Specifi-
rial. Dielectric breakdown voltage tests in air at room tempera-
cation D5423 Type II.
ture are periodically made to determine the time of aging at
6.4 Micrometer—The micrometer shall be of the dead-
each test temperature required to reduce the breakdown voltage
weight type specified in Methods C or D of Test Methods
to a value of 12 kV/mm (300 V/mil) of original thickness.
D374, having a pressor foot 6.35 mm 6 0.03 mm (0.25 in. 6
These thermal life values are used to construct a thermal
0.001 in.) in diameter and an anvil of at least 50 mm (2 in.) in
endurance graph by means of which temperature indices are
diameter and shall exert a pressure of 0.17 MPa 6 0.01 MPa
estimated corresponding to a thermal life as specified in the
(25 psi 6 2 psi) on the anvil.
material specification or as agreed upon between the user and
the supplier.
7. Test Specimens
NOTE 1—This test method is not applicable to materials having an
initial dielectric breakdown voltage of less than 12 kV/mm (300 V/mil) of 7.1 Test specimens shall be at least 250 mm (9.84 in.) long
original thickness unless lower endpoint values are agreed upon or
by 130 mm (5.12 in.) wide, with the machine direction parallel
indicated in the applicable material specifications.
to the longer direction.
5. Significance and Use
7.2 A set of test specimens consists of five specimens.
5.1 A major factor affecting the life of insulating materials is Prepare one set for initial (unaged) tests and five sets for each
thermal degradation. Other factors, such as moisture and aging temperature chosen (15 sets for three temperatures).
Insulation Thickness Dimension R Dimension H Dimension D
mm in. mm in. mm in. mm in.
0.18 0.007 4.55 0.179 8.15 0.321 8.71 0.344
0.25 0.010 6.48 0.255 6.22 0.245 2.45 0.490
0.30 0.012 7.77 0.306 4.93 0.194 4.94 0.588
Tolerance for R and D = 60.03 mm (0.001 in.)
Tolerance for H = 60.05 mm (0.002 in.)
FIG. 1 Curved Electrode Details
D1830 − 17 (2024)
NOTE 3—This is conveniently accomplished by the following
procedure, as an example: In the case of full-width material in rolls or
sheets, select an area sufficient to provide a panel about 1 m (3.28 ft) wide
by 3 m (9.84 ft) long. Using a suitable marking device, construct a grid of
7 lines spaced 130 mm (5.12 in.) across and 12 lines spaced 250 mm
(9.84 in.) down, with an edge margin of about 50 mm (1.97 in.) on each
side. This will provide 84 boxes, each delineating a test specimen. Number
the boxes consecutively across and down the grid. Using a set of random
numbers, obtain a selection of 16 sets of test specimens. In the case of slit
material in rolls, number specimens as removed from the roll and obtain
a random selection of test sets as in 8.1.
9. Selection of Test Temperatures
9.1 Expose the material at not less than three temperatures.
Any temperature that gives a thermal life of less than 100 h is
considered too high to be used in this evaluation. Choose the
lowest temperature such that (1) a thermal life of at least
5000 h is obtained and (2) it shall not be more than 25 °C
higher than the estimated temperature index. Exposure tem-
peratures shall differ by at least 20 °C.
9.2 Select exposure temperatures in accordance with those
shown in Table 1 as indicated by the anticipated temperature
index of the material under test. It is recommended that
exploratory tests be first made at the highest temperature to
obtain data establishing the validity of the 100 h minimum life
requirement (see 9.1), and that this be used as a guide for the
selection of the lower test temperatures.
10. Procedure
FIG. 2 Curved Electrode and Holder
10.1 Warning—Lethal voltages are a potential hazard
during the performance of this test. It is essential that the test
apparatus, and all associated equipment electrically connected
7.3 In the case of coated glass fabrics, make tests on
to it, be properly designed and installed for safe operation.
0.18 mm (0.007 in.) material having 0.08 mm (0.003 in.) or
Solidly ground all electrically conductive parts which it is
0.10 mm (0.004 in.) base cloth, or on 0.25 mm (0.010 in.) or
possible for a person to contact during the test. Provide means
0.30 mm (0.012 in.) material having respectively 0.10 mm
for use a
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