Small electromagnet design guidelines.
Small electromagnet design guidelines.
(OP)
I've recently built a very small electromagnet the size of a pencil eraser. It works, but I would like to improve it. It is not a high precision application- right now I'm just shooting for "better". I already understand that I can use more turns of a thinner wire to yield a coil which operates at higher voltage and lower current, or reverse that and have a lower voltage higher current setup- maybe the overall watts remains the same and the resultant flux is the same, or maybe one would make the case that more turns can fit onto this coil when they are a smaller diameter wire and so that is the way to maximize gauss in something like this. (random, intermittent 1 second pulses).
Secondly, I took a guess at the core profile ratio and diameter- I think right now my diameter is around .1" and the overall diameter at the flanges is around .24" What dimension(s) will most effect my overall magnetic pull? Are the steel (I don't have any pure iron handy) flanges helping, hurting, or not effecting my magnetic attraction? I could press on some plastic or other material flanges if needed. Their purpose now is just to contain the wire. I also have an opportunity to make the design a little bit longer if necessary, and I may order a soft iron core if the performance improvement would be significant. Thanks for any general suggestions!
Secondly, I took a guess at the core profile ratio and diameter- I think right now my diameter is around .1" and the overall diameter at the flanges is around .24" What dimension(s) will most effect my overall magnetic pull? Are the steel (I don't have any pure iron handy) flanges helping, hurting, or not effecting my magnetic attraction? I could press on some plastic or other material flanges if needed. Their purpose now is just to contain the wire. I also have an opportunity to make the design a little bit longer if necessary, and I may order a soft iron core if the performance improvement would be significant. Thanks for any general suggestions!





RE: Small electromagnet design guidelines.
We can estimate the field, and size the core.
The flanges should not be steel.
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P.E. Metallurgy, Plymouth Tube
RE: Small electromagnet design guidelines.
Thanks!
RE: Small electromagnet design guidelines.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: Small electromagnet design guidelines.
Using a steel flange will produce a lower fields strength, but it will be over a larger area. So you need to know what strength and shape of field you are after. There are lots of tricks in this.
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P.E. Metallurgy, Plymouth Tube
RE: Small electromagnet design guidelines.
EdStainless- Thanks! That type of general tip is just what I'm looking for. Dgallup: I can vary the power quite a bit, at least on the prototype. Anywhere from 2-30v dc is pretty easy to manage for this version so long as we don't burn out the coils. Even your lowest spec speed would be fine for this application I'm sure. Force/range would be the area of highest concern, and per ES's comment it sounds like I need to get rid of my flange(s?). I'd like a focused, strong, field. I will try to get more information to better define the existing info, but I don't have those #'s just yet. The flanges do serve a valuable purpose of containing those coils though, so if you have a suggestion for what material they can/should be (instead of steel)- I'd love to hear it.
RE: Small electromagnet design guidelines.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: Small electromagnet design guidelines.
Thanks! So plastic- that's easy enough, although for your production I'd guess cost is a bigger motivator. My motivation on the prototype would be to have very small and thin flanges, and that works a bit counter toward using plastic as opposed to something that will stay in place better on a metal core with only a thin line in contact. I may just machine a full bobbin with as thin an interior wall as I can manage, but that will subtract from the amount of copper I can fit (or core diameter).
RE: Small electromagnet design guidelines.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: Small electromagnet design guidelines.
RE: Small electromagnet design guidelines.
Can you estimate turns or the field strength? If it is below the saturation of the iron core then you could make core smaller and add more turns.
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P.E. Metallurgy, Plymouth Tube