Discussion Overview
The discussion revolves around calculating the torque that a fan would exert on a 5/8" hex shaft turning at 90 RPM, with a specific load requirement of 2.7 N.m. Participants explore various methods to achieve this torque, including the use of fans and alternative loading mechanisms, while considering the unique conditions of the shaft being housed in a dust box.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Experimental/applied
Main Points Raised
- One participant questions the precision of the 2.7 N.m load, suggesting that predicting the torque from a fan in a dust box is challenging due to altered airflow conditions.
- Another participant proposes using a prony brake attached to a socket on the shaft as a method to measure torque, suggesting a DIY approach or purchasing a commercial version.
- There is a suggestion that a DC gear motor could be used to load the shaft indefinitely, with the ability to adjust the torque by varying the electrical load.
- Concerns are raised about the speed of 90 RPM being too slow for effective use of a motor/generator setup, indicating a need for gearing.
- Some participants express uncertainty about the predictability of torque due to potential losses in the gearbox when using a geared motor.
- A link to a fan brake dynamometer design is shared, with a note about possible pressure pulses affecting performance due to the design constraints.
Areas of Agreement / Disagreement
Participants express differing views on the feasibility of accurately calculating the torque produced by a fan under the specified conditions. There is no consensus on the best approach to achieve the desired torque, and multiple competing methods are discussed.
Contextual Notes
The discussion highlights limitations related to the specific conditions of the dust box, the precision of the torque requirement, and the potential variability in performance due to mechanical losses in gear systems.