ASTM D5374-93(2005)
(Test Method)Standard Test Methods for Forced-Convection Laboratory Ovens for Evaluation of Electrical Insulation
Standard Test Methods for Forced-Convection Laboratory Ovens for Evaluation of Electrical Insulation
SIGNIFICANCE AND USE
It is essential that ovens used for thermal evaluation of insulating materials be capable of maintaining uniform conditions of temperature and air circulation over the extended periods of time that are required for conducting these tests. Specification D 5423 specifies the permissible deviations from absolute uniformity that have been generally accepted internationally for these ovens. These test methods include procedures for measuring these deviations and other specified characteristics of the ovens.
SCOPE
1.1 These test methods cover procedures for evaluating the characteristics of forced-convection ventilated electrically-heated ovens, operating over all or part of the temperature range from 20C above the ambient temperature to 500C and used for thermal endurance evaluation of electrical insulating materials.
1.2 These test methods are based on IEC Publication 216-4-1, and are technically identical to it. This compilation of test methods and an associated specification, D 5423, have replaced Specification D 2436.
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.
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Designation: D5374 − 93(Reapproved 2005) An American National Standard
Standard Test Methods for
Forced-Convection Laboratory Ovens for Evaluation of
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Electrical Insulation
This standard is issued under the fixed designation D5374; 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 These test methods cover procedures for evaluating the 3.1 Refer to the terminology section of Specification
characteristics of forced-convection ventilated electrically- D5423.
heated ovens, operating over all or part of the temperature
4. Significance and Use
range from 20°C above the ambient temperature to 500°C and
used for thermal endurance evaluation of electrical insulating
4.1 It is essential that ovens used for thermal evaluation of
materials.
insulating materials be capable of maintaining uniform condi-
1.2 These test methods are based on IEC Publication 216- tions of temperature and air circulation over the extended
periods of time that are required for conducting these tests.
4-1, and are technically identical to it. This compilation of test
methods and an associated specification, D5423, have replaced Specification D5423 specifies the permissible deviations from
absolute uniformity that have been generally accepted interna-
Specification D2436.
tionallyfortheseovens.Thesetestmethodsincludeprocedures
1.3 This standard does not purport to address all of the
for measuring these deviations and other specified character-
safety concerns, if any, associated with its use. It is the
istics of the ovens.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Apparatus
bility of regulatory limitations prior to use.
5.1 Multi-PointRecordingPotentiometer, having provisions
2. Referenced Documents for at least nine iron-constantan or chromel-alumel
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thermocouples, with scale readings to 0.1°C or less. Use of a
2.1 ASTM Standards:
data processor or a data logger may be helpful in reducing the
D2436 Specification for Forced-Convection Laboratory Ov-
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number of calculations required.
ens for Electrical Insulation (Withdrawn 1994)
D5423 Specification for Forced-Convection Laboratory Ov- 5.2 Calibrated Iron-Constantan or Chromel-Alumel
ens for Evaluation of Electrical Insulation
Thermocouples, using 0.5-mm diameter or smaller wire and
having a junction size not over 2.5 mm long. If calibrated
2.2 Other Document:
thermocouples are not available, thermocouples made from a
IEC Publication 216-4-1 Guide for the Determination of
single spool of thermocouple wire may be used provided that,
Thermal Endurance Properties of Electrical Insulating
when placed within 10 mm of each other without touching in
Materials, Part 4—Aging Ovens, Section 1—Single-
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an oven chamber at 200°C, they give values for temperature
Chamber Ovens
that do not differ from each other by more than 0.2°C.
5.3 A temperature measuring system other than thermo-
1 couples and a potentiometer may be used, provided that the
These test methods are under the jurisdiction of ASTM Committee D09 on
Electrical and Electronic Insulating Materials and are the direct responsibility of
sensitivity, accuracy, and response time are at least equivalent
Subcommittee D09.17 on Thermal Characteristics.
to that of the equipment described above, and that the objec-
Current edition approved Sept. 1, 2005. Published October 2005. Originally
tives of 6.2.3 relative to minimization of heat conduction
approved in 1993. Last previous edition approved in 1999 as D5374 – 93 (1999).
effects can be met.
DOI: 10.1520/D5374-93R05.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.4 Thermal Lag Time Specimen, consisting of a solid brass
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
cylinder, 10 mm in diameter and 55 mm long, with one
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
junction of a differential thermocouple soldered to the surface
3
The last approved version of this historical standard is referenced on
midway between the ends. The other junction of the thermo-
www.astm.org.
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couple must be capable of being moved at least 80 mm away
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. from the brass cylinder. An appropriate temperature indicator
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D5374 − 93 (2005)
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