ASTM D1830-99(2005)

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An American National Standard
Designation:D1830–99 (Reapproved 2005)
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 Department of Defense.
1. Scope D374 Test Methods for Thickness of Solid Electrical Insu-
lation
1.1 This test method provides a procedure for evaluating
D5423 Specification for Forced-Convection Laboratory
thermal endurance of flexible sheet materials by determining
Ovens for Evaluation of Electrical Insulation
dielectric breakdown voltage at room temperature after aging
2.2 Institute of Electrical and Electronics Engineers Pub-
in air at selected elevated temperatures. Thermal endurance is
lications:
expressed in terms of a temperature index.
IEEE No. 1 General Principles for Temperature Limits in
1.2 This test method is applicable to such solid electrical
the Rating of Electrical Equipment
insulating materials as coated fabrics, dielectric films, compos-
IEEE No. 101A Guide for the Statistical Analysis of Ther-
ite laminates, and other materials where retention of flexibility
mal Life Test Data (including Appendix A)
after heat aging is of major importance (see Note 4).
2.3 IEC Publications:
1.3 This test method is not intended for the evaluation of
IEC216 GuidefortheDeterminationofThermalEndurance
rigid laminate materials nor for the determination of thermal
Properties of Electrical Insulating Materials (Parts 1 and
endurance of those materials which are not expected or
2)
required to retain flexibility in actual service.
1.4 The values stated in acceptable metric units are to be
3. Terminology
regarded as the standard. The values in parentheses are for
3.1 Definitions:
information only.
3.1.1 temperature index, n—a number which permits com-
1.5 This standard does not purport to address all of the
parison of the temperature/time characteristics of an electrical
safety concerns, if any, associated with its use. It is the
insulatingmaterial,orasimplecombinationofmaterials,based
responsibility of the user of this standard to establish appro-
on the temperature in degrees Celsius which is obtained by
priate safety and health practices and determine the applica-
extrapolating theArrhenius plot of life versus temperature to a
bility of regulatory limitations prior to use. For a specific
specified time, usually 20 000 h.
hazard statement, see 10.1.
3.1.2 thermal life, n—the time necessary for a specific
2. Referenced Documents property of a material, or simple combination of materials, to
2 degrade to a defined end point when aged at a specific
2.1 ASTM Standards:
temperature.
D149 Test Method for Dielectric Breakdown Voltage and
3.1.3 thermal life curve, n—a graphical representation of
Dielectric Strength of Solid Electrical Insulating Materials
thermal life at a specified aging temperature in which the value
at Commercial Power Frequencies
of a property of a material, or a simple combination of
materials, is measured at room temperature and the values
This test method is under the jurisdiction of ASTM Committee D09 on
plotted as a function of time.
Electrical and Electronic Insulating Materials and is the direct responsibility of
3.2 Definitions of Terms Specific to This Standard:
Subcommittee D09.19 on Dielectric Sheet and Roll Products
Current edition approved Sept. 1, 2005. Published October 2005. Originally
approved in 1961. Last previous edition approved in 1999 as D1830 – 99. DOI:
10.1520/D1830-99R05.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036.
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D1830–99 (2005)
3.2.1 thermal endurance graph—a straight-line plot of the 6. Apparatus
logarithm of thermal life in hours versus the reciprocal of the
6.1 Electrode Test Fixture—The fixture shall be in accor-
absolute aging temperature in kelvins (also known as the
dance with the dimensions shown in Fig. 1 and Fig. 2.
Arrhenius plot).
Electrodes shall be of polished brass, with the upper electrode
having a mass of 1.8 6 0.05 kg (4.0 6 0.1 lb).
4. Summary of Test Method
6.2 Dielectric Breakdown Test Set—The set shall meet the
4.1 Specimens are aged in air at a minimum of three
requirements of Test Method D149.
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-
eachtesttemperaturerequiredtoreducethebreakdownvoltage
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,havingapressorfoot6.35 60.03mm(0.25 60.001in.)
These thermal life values are used to construct a thermal
in diameter and an anvil of at least 50 mm (2 in.) in diameter
endurance graph by means of which temperature indices may
and shall exert a pressure of 0.17 6 0.01 MPa (25 6 2 psi) on
be estimated corresponding to a thermal life as specified in the
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
7.1 Test specimens shall be at least 250 mm (9.84 in.) long
initial dielectric breakdown voltage of less than 12 kV/mm (300V/mil) of
by 130 mm (5.12 in.) wide, with the machine direction parallel
original thickness unless lower endpoint values are agreed upon or
to the longer direction.
indicated in the applicable material specifications.
7.2 A set of test specimens consists of five specimens.
5. Significance and Use Prepare one set for initial (unaged) tests and five sets for each
aging temperature chosen (15 sets for three temperatures).
5.1 Amajorfactoraffectingthelifeofinsulatingmaterialsis
7.3 In the case of coated glass fabrics, make tests on
thermal degradation. Other factors, such as moisture and
0.18-mm (0.007-in.) material having 0.08-mm (0.003-in.) or
vibration, may cause failures after the material has been
0.10-mm (0.004-in.) base cloth, or on 0.25-mm (0.010-in.) or
weakened by thermal degradation.
0.30-mm (0.012-in.) material having respectively 0.10-mm
5.2 Electrical insulation is effective in electrical equipment
(0.004-in.) or 0.13-mm (0.005-in.) base cloth.
only as long as it retains its physical and electrical integrity.
Thermal degradation may be characterized by weight change,
NOTE 2—Experience has shown that unrealistically extended life data
porosity, crazing, and generally a reduction in flexibility, and is
usually result when the base fabrics of glass exceed the thicknesses
usually accompanied by an ultimate reduction in dielectric
specified previously for the corresponding coated thicknesses. Similar
breakdown voltage. data are not available for other types of coated fabrics, and the user of this
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
D1830–99 (2005)
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 temperatures 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
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
to it, be properly designed and installed for safe operation.
Solidly ground all electrically conductive parts which it is
possible for a person to contact during the test. Provide means
for use at the completion of any test to ground any parts which
were at high voltage during the test or have the potential for
acquiring an induced charge during the test or retaining a
charge even after disconnection of the voltage source. Thor-
FIG. 2 Curved Electrode and Holder
oughly instruct all operators as to the correct procedures for
performing tests safely. When making high voltage tests,
particularly in compressed gas or in oil, it is possible for the
test method is urged to investigate this relationship to determine similar
limitations, if any. energy released at breakdown to be suf
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