IEC 60947-8:20 21规定了控制单元的要求，该控制单元响应旋转电机和工业应用中包含的PTC热敏电阻来控制开关设备。 这第二版取消并取代了2003年出版的第一版，修正案1:20 06和修正案2:20 11。本版构成技术修订版。 与上一版相比，此版本包括以下重大技术变更: 安全性方面涉及: 一般方面； 有限能量电路； 电子电路； 符合IEC 60947-1:20 20； 断线检测功能； 术语检测器被热敏电阻取代； 参考IEC 60738-1-4。

IEC 60947-8:2021 specifies requirements for control units, which control a switching device in response to the PTC thermistors incorporated in rotating electrical machines and the industrial application.
This second edition cancels and replaces the first edition published in 2003, Amendment 1:2006 and Amendment 2:2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:

1. safety aspects related to:

• general aspects;
• limited energy circuits;
• electronic circuits;

2. alignment to IEC 60947-1:2020;
3. wire break detection function;
4. the term detector is replaced by thermistor;
5. reference to IEC 60738-1-4.