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ASTM D3145-20(2025)
Standard Test Method for Thermal Endurance of Electrical Insulating Varnishes by Helical Coil Method
Standard Test Method for Thermal Endurance of Electrical Insulating Varnishes by Helical Coil Method
D3145-20R25
ASTM|D3145-20R25|en-US
Standard Test Method for Thermal Endurance of Electrical Insulating Varnishes by Helical Coil Method
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D3145 Standard Test Method for Thermal Endurance of Electrical Insulating Varnishes by Helical Coil Method>
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BOS Vol. 10.02 Committee D09
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Significance and Use
5.1 This test method is used to determine the effect of exposure to elevated temperatures on the bond strength of combinations of magnet wire insulations and electrical insulating varnishes. The results are used as a guide for the comparison and selection of varnishes and combinations of varnishes and magnet wire insulation for specific applications. Test Methods D1932 and D3251 describe additional tests for determining the thermal endurance of insulating varnishes. A comprehensive evaluation of thermal characteristics includes a comparison of the thermal endurance determined in these different ways.
5.2 This test method is useful for research and product qualifications purposes.
Scope
1.1 This test method covers the determination of the thermal endurance of electrical insulating varnishes alone or in combinations with magnet wire insulation. Changes in the helical coil bond strength are used as the test criteria. The coils are made from bare aluminum or copper wire, or from film- or fiber-insulated magnet wire.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
Note 1: There is no similar or equivalent IEC standard.
1.3 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 precautionary statement, see Section 7.
1.4 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.