本标准适用于同步电机完整励磁系统及其部件的高电位测试。IEEE Std 421.1（TM）中描述了励磁系统的部件。连接到整流桥输入侧或输出侧的辅助装置暴露在类似的励磁系统应力下，并包含在本标准的要求中。此类设备包括温度指示器、传感器、仪表、磁场断路器、放电电阻器、撬棍等。本标准不包括同步电机磁场绕组。

This standard applies to high-potential testing of complete excitation systems and their components for synchronous machines. The components of the excitation system are described in IEEE Std 421.1(TM). Auxiliary devices connected to either the input or output side of the rectifier bridge are exposed to similar excitation system stresses and are included in the requirements of this standard. Examples of such devices include temperature indicators, transducers, meters, field circuit breaker, discharge resistor, crowbar, etc. This standard does not cover the synchronous machine field winding.