Do these Resistance torque values for my setup make sense?

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SUMMARY

The discussion focuses on the relationship between the separation distance of permanent neodymium magnets and the resistance torque experienced by a conductive disc spinning between them. The experiment utilized a small DC motor and equidistant neodymium magnets to create a magnetic braking system, measuring resistance torque values at various distances. The results indicate a predictable trend in resistance torque as the separation distance changes, aligning with principles of electromagnetism and rotational mechanics.

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  • Understanding of electromagnetism principles, particularly related to magnetic fields and eddy currents.
  • Familiarity with rotational mechanics and torque calculations.
  • Experience with experimental design and data analysis in physics.
  • Knowledge of DC motors and their operational characteristics.
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extendedfaker
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Thread moved from the technical forums to the schoolwork forums
TL;DR Summary: research question: “How does the Separation distance of permanent neodymium magnets (m) affect the Resistance torque (Nm) of a conductive disc spinning in between them?”
The objective is to predict the relationship between Resistance torque that tends to slow down the disk and the Separation distance of magnets, using laws of electromagnetism and rotational mechanics to create a theoretical model and testing the model’s validity through experimentation.

I used a small DC motor with small equidistant Neodymium magnets placed on opposite sides to make a mini magnetic braking system and adjusted their separation distance to calculate the resulting resitance torque due to eddy currents. Do these results make sense? Note: My setup was quite small, with the disc being 6 cm in diameter.
Separation distance
(l0.0001m)		Mean Period
(Tavg)		Absolute uncertainty
in T
Tavg/s		Fractional uncertainty in T
(Tavg/Tavg)		Resistance Torque
(τ/Nm)		Absolute uncertainty in τ
(τ/Nm)
0.00940.03430.00110.03060.042200.0071
0.01040.17320.00210.01210.032000.0042
0.01140.13770.00220.01600.028840.0061
0.01240.09660.00440.04550.022230.0041
0.01340.08230.00190.02310.018210.0018
0.01440.06820.00150.02130.014860.0027
0.01540.05830.00420.07120.011260.0022
0.01640.05500.00130.02270.009680.0016
0.01740.04670.00110.02250.008740.0017
 
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Welcome to PF.

extendedfaker said:
The objective is to predict the relationship between Resistance torque that tends to slow down the disk and the Separation distance of magnets, using laws of electromagnetism and rotational mechanics to create a theoretical model and testing the model’s validity through experimentation.
What info have you found so far for Eddy Current Braking? Please post links to your technical reading about this subject. Thanks.

Also, using my Mentor superpowers, I'm pretty sure this "research" is for your schoolwork, so I will move your thread to the schoolwork forums for you now.
 
Do you know the general rule-of-thumb of how the magnetic field strength varies with distance? (If not, try a Google search.)

Does the Resistance Torque follow this same trend?

Don't expect the numbers to perfectly match the theory, experiments rarely do!

Cheers,
Tom
 
berkeman said:
Welcome to PF.


What info have you found so far for Eddy Current Braking? Please post links to your technical reading about this subject. Thanks.

Also, using my Mentor superpowers, I'm pretty sure this "research" is for your schoolwork, so I will move your thread to the schoolwork forums for you now.
https://www.mdpi.com/2227-7080/12/4/50