The purpose of this project is to reduce the frequent blower motor failures due to an internal temp sensor. When the senor experiences an elevated temp, it will cut power to the fan. The sensor protects the coils of the motor and so it could not be removed, but that the fan is being used in a harsh environment and upgrading it is not a cost effective solution.
The solution was the design of a ducted heat sink that channeled ambient air from the fan, through a duct that acted as a heat sink for the end bell plate. The end bell plate is the support for the rear bearing for the shaft, which was determined to be a significant source of heat within the fan. The hope was to utilize the greatest temp gradient available (the ambient air and the bearing plate) for heat transfer, in order to reduce the steady state temp of the fan, thereby reducing the potential of the sensor tripping. The modification was able to reduced the steady state temp near the sensor by 15 degrees F.
