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.