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bird777
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 « on: February 20, 2008, 03:40:27 03:40 »

Hi,

Could anyone help me how to design electromagnetic coil?
I have a plastic part and I would like to move it linear:
1. if the coil on the plastic part and the permanent magnet fix, or
2. a permanent magnet is in the plastic part and the coil is fix outside the plastic part.

Thx,
Bird
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Todporn
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 « Reply #1 on: February 25, 2008, 02:50:03 02:50 »

Hello bird777,

I'm not sure that I fully understand your post, but I think that you were talking about building a Linear Motor.  If so, there are tons of information out there on the internet just googles 'linear motor'.   It would be easier to build (according to your post) a linear motor by fixing the coil(s) on your plasting part and letting the permanent magnet be the moving part.

HTH
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bird777
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 « Reply #2 on: February 26, 2008, 09:11:22 09:11 »

Hello,

I only need for an electromagnet what can be moving an iron pipe inside when I connect power to the coil. When power off a spring push the iron pipe back.
How can I calculate the turns of coil, the current, the wire square and the spring's force? I am going to use 48 V DC.
I know the weight of pipe and its dimensions.

Bird
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Todporn
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 « Reply #3 on: February 26, 2008, 01:00:29 13:00 »

Hello,

I think I understand what you are trying to do now.  You need to calculate an energy balance equation like this..

Energy input from electric sources = Mechanical energy output + Increase in energy stored in electric field + Energy converted into heat

You also need to know the permeability value of your iron pipe and coil's dimensions in order to properly calculate for coil's inductance. The number of turns can be approximated from calculated inductance...  Well, that's my two cents..It has been a long time since I studied 'Electromechanical Energy Conversion'.  You may find this link a good starting point...

http://ee.sharif.edu/~machine2/texts/Electric%20Machines%20-%20Fitzgerald%20PDF/electric%20machine%20Ch03.pdf

HTH
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oscar.inc
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 « Reply #4 on: February 27, 2008, 06:05:05 18:05 »

the magnetic flux is created for N helices of wire, for which it(he,she) circulates I amperes's current, producing then a force magnetomotriz given for:

F = (N * I) / 0.796 (1) (* it is a sign of multiplication)
Where:

F: It(He,She) forces magnetomotriz in ampere.espira N: I number of helices I: current in amperes
1.2 MAGNETIZING FORCE------------------------The magnetizing force is defined as the force magnetomotriz by unit of length of the way.

H=F/l (2)
Where:

H:fuerza magnetizing in LENZ F:fuerza magnetomotriz in amper.espira l:longitud of the way cm

The permeability this (Mu) defined by the relation:

Mu=B/H (3)
Where:

Mu: Permeability B: Density of flow, in GAUSS H: magnetizing Force in Lenz In the air, H is numerically equal to the density of flow B.

The permeability is the equivalent one of the conductivity in the electrical circuits..
The permeability in the iron is not constant, since several(different) with the flow.
The relation between(among) B, H and Mu appears in B-H's curves of the iron,

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otakis
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 « Reply #5 on: March 14, 2008, 03:35:45 15:35 »

hi all,
where can i found infos for a simple coilgun?

thanks!
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