ISO 12759-2:2019

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.