Calculation of torque, momentum

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Discussion Overview

The discussion revolves around the calculation of torque in a small motor setup, specifically comparing torque measurements obtained from a load cell at different distances from the motor shaft. Participants explore whether the torque values remain consistent despite variations in the measurement points.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant describes a device designed to measure torque using a load cell and questions if torque measurements at different distances (d and d1) yield the same results.
  • Another participant prompts a consideration of the definition of torque, questioning if moments can be equal when forces are the same but lever arms differ.
  • A participant acknowledges the definition of torque but points out that the force on the load cell would vary between the two measurement scenarios.
  • Another participant interprets the drawing and asserts that the torque remains constant regardless of the measurement point, suggesting that the reaction forces differ due to the extended casing.
  • A participant confirms the calculations made using the load cell data and inquires about the presence of a brake on the flywheel or if the focus is solely on torque during acceleration.

Areas of Agreement / Disagreement

Participants express differing views on whether the torque measurements at different distances yield the same results, indicating a lack of consensus on this matter.

Contextual Notes

Participants reference a diagram that is not fully detailed, which may limit the clarity of the discussion regarding the torque measurement setup.

johnaguiar
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Hi,
good afternoon

the problem is this: This device was assembled with the purpose of calculating the torque of a small motor. It measures the force F through a charge cell. The calculations performed for the moment were made using the data provided by the load cell and distance "d". However, the torque of an engine is traditionally calculated as the force established between the motor shaft and a load cell, as would be the case with the distance "d1". I would just like to know if the two moments are the same.
 

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johnaguiar said:
I would just like to know if the two moments are the same.
Did you look at the definition of a moment? When the force is the same, but the lever arms are different, can the moments be equal?
 
A.T. said:
Did you look at the definition of a moment? When the force is the same, but the lever arms are different, can the moments be equal?
Yes i know the definition. The problem is that also the force on the load cell would be different on the two cases.
 
johnaguiar said:
Yes i know the definition. The problem is that also the force on the load cell would be different on the two cases.
What two cases? You posted only one crude diagram, and didn't even mark the motor.
 
If I understood your drawing correctly, the torque is the same no matter where you measure it.

If you take a motor casing and its shaft, the torque is the same from the point of view of the casing or the shaft (one reacting to the other). If the casing is attached to a plate supporting it (like it seems to be in your drawing), you are just extending the casing. The reaction force will be smaller because of the larger 'casing', but that is just because the torque is the same.
 
johnaguiar said:
The calculations performed for the moment were made using the data provided by the load cell and distance "d"

That's correct.

Is there a brake on the flywheel or are you just interested in the torque while the flywheel is accelerating?
 

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