Do these Resistance torque values for my setup make sense?

[extendedfaker]

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)
0.0094	0.0343	0.0011	0.0306	0.04220	0.0071
0.0104	0.1732	0.0021	0.0121	0.03200	0.0042
0.0114	0.1377	0.0022	0.0160	0.02884	0.0061
0.0124	0.0966	0.0044	0.0455	0.02223	0.0041
0.0134	0.0823	0.0019	0.0231	0.01821	0.0018
0.0144	0.0682	0.0015	0.0213	0.01486	0.0027
0.0154	0.0583	0.0042	0.0712	0.01126	0.0022
0.0164	0.0550	0.0013	0.0227	0.00968	0.0016
0.0174	0.0467	0.0011	0.0225	0.00874	0.0017

 

[berkeman]

Welcome to PF.

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.

 

[Tom.G]

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

 

[extendedfaker]

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