本文件对风机效率进行了分类。它适用于使用以下特定组件组合的所有电机驱动风扇系统: a） 根据公认的性能标准确定的风扇气流性能； b） 本文件规定的标称电机效率的多相感应电机； 注1:明确排除了其他类型的电机。 c） 用于单台电机的脉宽调制变频驱动器（VFD）； 注2:不包括为多个并联风扇电机提供服务的单个VFD。 d） 使用V带、平带、齿带或联轴器的机械动力传动。

This document establishes a classification for fan efficiency. It applies to all electric-motor-driven fan systems that utilize a specific combination of components as defined below: a) fan airflow performance determined in accordance with an accepted performance standard; b) polyphase induction motors with nominal motor efficiency specified in this document; NOTE 1 Other types of motors are explicitly excluded. c) pulse-width modulated variable frequency drives (VFDs) for use with single motors; NOTE 2 Single VFDs that service multiple, parallel fan motors are excluded. d) mechanical power transmissions that utilize V-belts, flat belts, cog belts or couplings.