IEC 60034-9:20 21 CMV包含官方标准及其注释版本。注释版本为您提供了一种快速简单的方法来比较IEC 60034-9:20 21版5.0和之前的IEC 60034-9:20 03+AMD1:2007 CSV版4.1之间的所有更改。此外，还提供了IEC TC 2专家的意见，以解释最相关变更的原因。 IEC 60034-9:20 21规定了确定旋转电机声功率级的测试方法，并根据lEC 60034-1规定了用于网络供电旋转电机工厂验收测试的最大A加权声功率级，具有根据lEC 60034-6的冷却方法和根据lEC 60034-5的保护程度，并具有以下特性:-交流或直流的标准设计，无需额外的特殊电气、机械或声学修改以降低声功率级 -额定输出从1 kW(或kVA)至5 500 kW(或kVA) -额定转速不大于3 750 min-1 第五版取消并取代了2003年出版的第四版及其2007年出版的修正案1。与上一版相比，此版本包括以下重大技术变更: a)在表2和表3中，现在涵盖冷却方法IC01、IC11、IC21和IC31、IC71、IC81。 b)本版增加了60 Hz机器的表3，而仅涵盖50 Hz机器的表2在级别上没有变化。 c)在表3中，添加A级是为了协调IEC和NEMA中的最高水平，而添加B级是为了协调IEC和NEMA中的最低、更具限制性的水平。d)条款“转换器电源引起的噪声增量的确定”已移至附件B，并更名为“转换器电源引起的典型噪声增量信息”。

IEC 60034-9:2021 CMV contains both the official standard and its commented version. The commented version provides you with a quick and easy way to compare all the changes between IEC 60034-9:2021 edition 5.0 and the previous IEC 60034-9:2003+AMD1:2007 CSV edition 4.1. Futhermore, comments from IEC TC 2 experts are provided to explain the reasons of the most relevant changes.

IEC 60034-9:2021 specifies test methods for the determination of sound power level of rotating electrical machines and specifies maximum A-weighted sound power levels for factory acceptance testing of network-supplied, rotating electrical machines in accordance with lEC 60034-1, having methods of cooling according to lEC 60034-6 and degrees of protection according to lEC 60034-5, and having the following characteristics:
- standard design, either AC or DC, without additional special electrical, mechanical, or acoustical modifications intended to reduce the sound power level
- rated output from 1 kW (or kVA) up to and including 5 500 kW (or kVA)
- rated speed not greater than 3 750 min–1

This fifth edition cancels and replaces the fourth edition, published in 2003 and its amendment 1, published in 2007. This edition includes the following significant technical changes with respect to the previous edition:
a) In Table 2 and Table 3 cooling methods IC01, IC11, IC21 and IC31, IC71, IC81 are now covered.
b) This edition adds Table 3 for 60 Hz machines, whereas Table 2, which covers only 50 Hz machines, has no change in levels.
c) In Table 3, grade A is added to harmonize the highest levels seen in IEC and NEMA, whereas grade B was added to harmonize the lowest, more restrictive levels seen in IEC and NEMA.
d) The clause “Determination of noise increments caused by converter supply” has been shifted to Annex B and renamed “Information on typical noise increments caused by converter supply”.