Help in designing electromagnets

AI Thread Summary
The discussion focuses on designing electromagnets for a system based on the MIT Actuated Workbench, specifically using a 1.9cm diameter and 3.8cm length configuration with 32-gauge copper wire. The original design operates at 27V and draws about 250mA, but the user seeks to optimize for more force and potentially use a standard 24V power supply. Calculating electromagnet strength involves understanding amp-turns per unit length and permeability, with suggestions to estimate the number of turns based on wire resistance. The user is also exploring simulation tools like FEMM and MaxFEM for design optimization. Overall, the thread emphasizes the need for clarity on electromagnet strength calculations and design adjustments.
Nmbr6
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Hi all,
First post, be gentle...

I'm trying to build a system based on the MIT Actuated Workbench.
They used electromagnets with the following spec:
1.9cm (0.75”) diameter x 3.8cm (1.5”) length, wound with 32-gauge copper wire with a total length resistance of 120-122 ohms, with no metal housings so to not focus the magnetic field.
They used 27 DC volts and draws about 250mA.

From what I read, it seamed to be an almost arbitrary choice though, so I was hoping to optimist the design to create more forces. I was also hoping to use a more standard 24V power supply (not sure why they used 27...)

I'm not sure where to start this process and I was hoping to get some advice.

I thought maybe some trial and error through a simulation tool could work, but tell me what you think (also for that, so far I saw recommendations for FEMM, MaxFEM, Vizimag, Elmer and OpenFOEM, so I could also use a recommendation for which one to use)

Thanks!
 
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Nmbr6 said:
so I was hoping to optimist the design to create more forces.

So is the question "how does one calculate strength of an electromagnet? " ? Any search engine should respond to that question.
The basic approach is amp-turns per unit length X permeability.
With 32 gage wire it's a sure bet they used copious turns and meager amps to get the amp-turn product they wanted.
You already know the amps, around ¼ .
To estimate # turns figure length of #32 to make 120 ohms. How many times will that wrap around a ¾ inch core?

The video you posted is long on applications but short on mechanical details.
They gave no clue how they detect position of a puck over the array of electromagnets.

Nmbr6 said:
I'm not sure where to start this process and I was hoping to get some advice.
It's hard to figure out what you are asking.
 
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