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.