IEC 60034-18-21:2012给出了用于或拟用于绕线式交流（a.c.）或直流（d.c.）旋转电机的绝缘系统的热评估和分类的试验程序。将候选绝缘系统的测试性能与具有可靠服务经验的参考绝缘系统的测试性能进行比较。与前一版相比，主要的技术变化体现在对比较数据进行评估时引入了一些基本的统计方法。 此外，该标准规定了不同试验程序的更简单使用。

IEC 60034-18-21:2012 gives test procedures for the thermal evaluation and classification of insulation systems used or proposed for use in wire-wound alternating current (a.c.) or direct current (d.c.) rotating electrical machines. The test performance of a candidate insulation system is compared to the test performance of a reference insulation system with proven service experience. The main technical changes with regard to the previous edition can be seen in the introduction of some basic statistical methods in the evaluation of comparative data. Moreover, the standard states a simpler use of different test procedures.