ASTM D2307-07a(2013)

Standard Test Method for Thermal Endurance of Film-Insulated Round Magnet Wire

SIGNIFICANCE AND USE
5.1 This test method is useful in determining the thermal endurance characteristics and thermal indices of film-insulated round magnet wire in air (see 1.3) (see Test Method D3251). This test method is used as a screening test before making tests of more complex systems or functional evaluation. It is also used where complete functional systems testing is not feasible.  
5.2 Experience has shown that film-insulated wire and electrical insulating varnishes or resins can affect one another during the thermal exposure process. Test Method D3251 provides indications on the thermal endurance for a combination of insulating varnish or resin and film insulated wire. It is possible that interaction between varnish or resin and film insulation will increase or decrease the relative thermal life of the varnish and film insulated wire combination compared with the life of the film insulated wire tested without varnish.  
5.3 The conductor type or the surface condition of the conductor will affect the thermal endurance of film-insulated magnet wire. This test method is used to determine the thermal endurance characteristics of film insulation on various kinds of conductors. The use of sizes other than those specified in 7.1.1 is permissible but is not recommended for determining thermal endurance characteristics.  
5.4 The temperature index determined by this test method is a nominal or relative value expressed in degrees Celsius at 20 000 h. It is to be used for comparison purposes only and is not intended to represent the temperature at which the film insulated wire could be operated.  
5.5 There are many factors that influence the results obtained with this test method. Among the more obvious are the following:  
5.5.1 Wire size and film thickness.  
5.5.2 Moisture conditions during proof voltage tests.  
5.5.3 Oven construction:
5.5.3.1 Velocity of air.
5.5.3.2 Amount of replacement air.
5.5.3.3 Elimination of products of decomposition during thermal exposure...
SCOPE
1.1 This test method covers determination of the thermal endurance of film-insulated round magnet wire in air at atmospheric pressure. It is not applicable to magnet wire with fibrous insulation, such as cotton or glass.  
1.2 This test method covers the evaluation of thermal endurance by observing changes in response to ac proof voltage tests. The evaluation of thermal endurance by observing changes in other properties of magnet wire insulation requires the use of different test methods.  
1.3 It is possible that exposure of some types of film insulated wire to heat in gaseous or liquid environments in the absence of air will give thermal endurance values different from those obtained in air. Consider this possibility when interpreting the results obtained by heating in air with respect to applications where the wire will not be exposed to air in service.  
1.4 It is possible that electric stress applied for extended periods at a level exceeding or even approaching the discharge inception voltage will change significantly the thermal endurance of film insulated wires. Under such electric stress conditions, it is possible that comparisons between materials will also differ from those developed using this method.  
1.5 This test method is similar to IEC 60172. Differences exist regarding specimen preparation.  
1.6 The values stated in inch-pound units are to be regarded as the standard. The SI units in parentheses are provided for information only.  
1.7 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.

General Information

• Status: Historical
• Publication Date: 31-Mar-2013
• ICS: 29.060.10 - Wires
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.17 - Fire and Thermal Properties

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: D2307 − 07a (Reapproved 2013)
Standard Test Method for
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Thermal Endurance of Film-Insulated Round Magnet Wire
This standard is issued under the fixed designation D2307; 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* 2. Referenced Documents
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2.1 ASTM Standards:
1.1 This test method covers determination of the thermal
D1676 Test Methods for Film-Insulated Magnet Wire
endurance of film-insulated round magnet wire in air at
D1711 Terminology Relating to Electrical Insulation
atmospheric pressure. It is not applicable to magnet wire with
D3251 Test Method for Thermal Endurance Characteristics
fibrous insulation, such as cotton or glass.
of Electrical Insulating Varnishes Applied Over Film-
1.2 This test method covers the evaluation of thermal
Insulated Magnet Wire
endurance by observing changes in response to ac proof
D5423 Specification for Forced-Convection Laboratory Ov-
voltage tests. The evaluation of thermal endurance by observ-
ens for Evaluation of Electrical Insulation
ing changes in other properties of magnet wire insulation
2.2 Other Standards:
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requires the use of different test methods.
IEC 60172 Statistical Analysis of Thermal Life Test Data
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IEEE 101 Statistical Analysis of Thermal Life Test Data
1.3 It is possible that exposure of some types of film
insulated wire to heat in gaseous or liquid environments in the
3. Terminology
absence of air will give thermal endurance values different
3.1 Definitions:
from those obtained in air. Consider this possibility when
3.1.1 temperature index, n—a number which permits com-
interpreting the results obtained by heating in air with respect
parison of the temperature/time characteristics of an electrical
to applications where the wire will not be exposed to air in
insulatingmaterial,orasimplecombinationofmaterials,based
service.
on the temperature in degrees Celsius which is obtained by
1.4 It is possible that electric stress applied for extended extrapolating theArrhenius plot of life versus temperature to a
periods at a level exceeding or even approaching the discharge specified time, usually 20 000 h.
inception voltage will change significantly the thermal endur-
3.1.2 thermal endurance, n—an expression for the stability
ance of film insulated wires. Under such electric stress
of an electrical insulating material, or a simple combination of
conditions, it is possible that comparisons between materials
materials, when maintained at elevated temperatures for ex-
will also differ from those developed using this method.
tended periods of time.
1.5 This test method is similar to IEC 60172. Differences
3.2 Definitions of Terms Specific to This Standard:
exist regarding specimen preparation.
3.2.1 specimen failure time, n—the hours at the exposure
temperature that have resulted in a specimen failing the proof
1.6 The values stated in inch-pound units are to be regarded
test (see 9.1).
as the standard. The SI units in parentheses are provided for
3.2.2 thermal endurance cycle, n—one oven exposure pe-
information only.
riod followed by a proof voltage test.
1.7 This standard does not purport to address all of the
3.2.3 time to failure, n—the log average hours calculated for
safety concerns, if any, associated with its use. It is the
a set of specimens, calculated from the individual specimen
responsibility of the user of this standard to establish appro-
failure times at an exposure temperature (see 9.2).
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
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This test method is under the jurisdiction of ASTM Committee D09 on the ASTM website.
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Electrical and Electronic Insulating Materials and is the direct responsibility of Available from International Electrotechnical Commission (IEC), 3 rue de
Subcommittee D09.17 on Fire and Thermal Properties. Varembé, Case postale 131, CH-1211, Geneva 20, Switzerland, http://www.iec.ch.
Current edition approved April 1, 2013. Published April 2013. Originally
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approved in 1964. Last previous edition approved in 2007 as D2307 – 07a. DOI: Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),
10.1520/D2307-07AR13. 445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331, http://www.ieee.org.
*A Summary of Changes section appears at the end of this standard
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