Exciting research day

Today I’ll be experimenting on a “ideal magnetic kreis” mainly to see if a person can get any kind of worthwhile pull in one direction or another from my super magnet.

Magnetics itself is a phenominoooo—…thing that has always interested me…actually probably like any science person. You can have a force interact with an object straight through the air without ever having to touch it. It’s pretty damn cool really.

In an ideal system (forgetting meddling things like physics ) You can calculate a magnets flux density and it’s strength with B = \frac{NI\mu}{l} where N is the amount of windings around your core, l the length of your windings I your amps and \mu = \mu _r \times \mu_o is the magnetic constant mulitiplied with the permability of your core material. When dealing with an ‘infinity’ long core and a copper winding.

If we look at what my system should have for a flux density and throw some numbers around;

B = \frac{498\times5\mathrm{A}\times\mu_0\times2000}{100\times10^{-3}\mathrm{m}} = 19.\mathrm{numbers}\times \pi\,\mathrm{T} Which, wow. that’s hella big.

Buuuut well, that’s not even remotely physically possible. (like I said, meddling physics…) In reality there are things that play very large roles in how powerful an electromagnet can be. Things like magnetic resistance or reluctance, electrical resistance, saturation and other stuff. Without going into details. The core I have is 99.95% pure iron. Which saturates around 2.3 Teslas.

My system is of course not just a infinity long pure ironcore. It has those arm things on it and the core itself is actually two separate cores with a 2mm air gap in between them. If you start to look at a less than ideal system the approximation of the my magnetic density starts to go down pretty drastically.

B = \frac{\Psi}{A} = \frac{NI}{\mathbb{R}A}

Where \mathbb{R} = \frac{l}{\mu*A} and A is the cross section of the circuit. Once I start throwing in some numbers there. My density drops down to around 1T. Which isnt bad…but most certainly doesn’t give me as powerful a magnet as I originally planned…and definitely not as high as ≈19.numbers π flux density.

When you start having to deal with that bastard physics, then of course things start getting a little depressing. \mathrm{e}^{\sqrt{2}}


Posted in R&D

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