SAE J 2873:2010-07-08

This SAE Recommended Practice is applicable to Electric Cooling Fan Assemblies used in vehicle cooling systems. This document outlines the critical mounting interface characteristics such that a common standard is possible.
Rationale:
The intent is to describe standard mounting interfaces for the motor to shroud attachment. Today this attachment varies with OEM and Supplier. This variation is arbitrary, adding cost, but not value. The concept of having bolt circle, number of attachments, spacing and diameter of those attachments is supported by the Supplier of Electric Cooling Fans such as Brose, Bosch, Denso (Asmo), Hyo Seong, Johnson Electric (Gate) and Nidec, Dong Yang..