1.1 本试验方法包括通过确定在高温下将清漆的介电击穿降低到适用于标准玻璃纤维织物的任意选择值所需的时间，来测定柔性电绝缘清漆的相对耐热性。 1.2 本试验方法不适用于在屏蔽试验（第节）中规定的高温暴露前弯曲时失去高百分比介电击穿电压的清漆 9 ). 此类清漆的示例是用于高速电枢和层压结构的清漆。此外，本试验方法不适用于在高温暴露期间变形充分的清漆，因此无法使用弯曲电极组件进行试验。 1.3 耐热性用温度指数表示。 1.4 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 注1: 没有同等的IEC或ISO标准。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 有关具体的危险说明，请参阅第节 7. . 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 影响绝缘材料长期性能的一个主要因素是热降解。在材料被热降解削弱后，水分和振动等因素可能会导致失效。 5.2 电气绝缘清漆只有在保持其物理和电气完整性的情况下才能有效地保护电气设备。 5.3 清漆的热降解会导致重量损失、孔隙率、龟裂，并且通常会降低柔韧性。清漆的劣化可以通过介电强度的降低来检测，因此，介电强度被用作本试验方法的失效标准。 5.4 由于振动和热膨胀，电绝缘清漆在使用中会发生弯曲。因此，该功能测试包括绝缘的弯曲和伸长。 本试验方法中使用的电极设计用于拉长试样2的外表面 % 在进行介质击穿测试时，与基础光纤的中性轴有关。

1.1 This test method covers the determination of the relative thermal endurance of flexible electrical insulating varnishes by determining the time necessary at elevated temperatures to decrease the dielectric breakdown of the varnish to an arbitrarily selected value when applied to a standard glass fiber fabric. 1.2 This test method does not apply to varnishes that lose a high percentage of their dielectric breakdown voltage when flexed before elevated temperature exposure as prescribed in the screening test (Section 9 ). Examples of such varnishes are those used for high speed armatures and laminated structures. Also, this test method is not applicable to varnishes which distort sufficiently during thermal elevated temperature exposure so that they cannot be tested using the curved electrode assembly. 1.3 Thermal endurance is expressed in terms of a temperature index. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Note 1: There is no equivalent IEC or ISO standard. 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 specific hazard statements, see Section 7 . 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. ====== Significance And Use ====== 5.1 A major factor affecting the long term performance of insulating materials is thermal degradation. It is possible that factors, such as moisture and vibration, will cause failures after the material has been weakened by thermal degradation. 5.2 An electrical insulating varnish is effective in protecting electrical equipment only as long as it retains its physical and electrical integrity. 5.3 The thermal degradation of the varnish results in weight loss, porosity, crazing, and generally a reduction in flexibility. Degradation of the varnish can be detected by a decrease in dielectric strength, which is therefore used as the failure criterion for this test method. 5.4 Electrical insulating varnishes undergo flexing in service due to vibration and thermal expansion. For this reason, this functional test includes flexing and elongation of the insulation. The electrodes used in this test method are designed to elongate the outer surface of the specimen 2 % with respect to the neutral axis of the base fiber while being tested for dielectric breakdown.