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Electromagnet

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seklum

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I am making an electro magnet using 15 feet of 14 guage electrical wire wrapping around a 3/4" by 1' giant screw thing. I was wonder if it will work if I have it wrapped inside the threads or will that effect it at all?

here it is (haven't finished wrapping)

**broken link removed**
 
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It will work fine but it will take a lot of amps at a very low voltage to work.
 
How can i get that to happen? (Sorry I'n no electrician lol)

Better yet, can I get, or make, a converter to plug into the wall to do this?
 
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What to you want the electromagnet to do? Electromagnets generate a stronger field if you have a horseshoe shaped core to complete the magnetic circuit. With a straight rod the magnetic field has to go from one end of the rod to the other. This long distance makes a weak magnetic field for a given ampere-turns.
 
I just want it to attract metal.

Can I make the core horseshoe shaped without getting a new rod? This thing was 7 bucks lol =P
And Not it won't bend.

I was thinking If I got some other metal, and like welded it onto that into a triangle would that be the same?
 
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For strong attraction to metal you want both poles of the electromagnet to touch the metal. Thus it would help if you welded another piece of (magnetic) material to make a triangle or U-shape magnet.

Don't know what best to power your magnet with. It would likely require many tens of amps at a few volts to generate a good magnetic field which is not easy to generate from standard power sources. Winding the coil with many turns of much smaller wire makes its much easier to power. It's the ampere-turns that determines the field intensity. Thus 20 turns at 1A is the same as 1 turn at 20A. Look at a wire table to determine the wire resistance for various size wire, and from that you can calculate how many feet of wire for a desired resistance for a given current and voltage.

For example, 28AWG wire has a resistance of .0649 ohms per foot. Thus if you wanted to power your magnet with a single D-cell at 1A of current (1.5Ω), you would wind 1.5Ω/.0649 = 23 ft. of wire on your magnet. If you used two D-cells, you would wind 46 ft. of wire, for about double the ampere-turns.
 
Beware if you have too few turns and a high current DC power supply, the wire will overheat and smoke or if the power supply isn't current limited, it will overheat.

You might add another layer of turns, which will make it more efficient too. You should be able to do this pretty neatly because the layer of turns will fit in the gaps.
 
A couple of NiMH batteries, insufferably, real C cells ( with a capacity of >4000mAh not AAs with extra padding).
 
Given that your 15 feet of 14 gauge wire has a resistance of around .0388 ohms your 1.2 volt batteries should provide around 31 amps of current through that wire.

Its going to get very hot rather fast and your batteries will die quickly as well!
 
Did the wire melt?

I would've thought it would've acted like a fuse.

use more turns, I'd say that if you want to run it off a 6V battery, multiply the wire length by 100, assuming tcmmech's calculations are correct.
 
My referance book shows 14 gauge enameled wire to be 2.59 ohms per 1000 feet. so (15/1000) x 2.59 = .0387 ohms.

On a car battery that should have been about 310 amps or the same average power draw as the starter. :eek:

Had you made good contact the 14 gauge wire should have burned the enamel off itself and burst it into flames in about half a second and welded itself to the steel bolt then melted the ends off in your hands.:D

Dang! survival of the fittest is getting sloppy. This should have been an easy take down. :rolleyes:
 
I was wearing a snow glove, and technically it was in a dune buggy, so probably not as power full as a regular car battery lol =) lucky me
 
You didn't say anything about enamel insulation, and you give no indication that you know what that even means. If your "giant screw thing" is iron, and your wire is the bare wire from electrical wiring then most of your current probably went through the "giant screw thing".

I'm with tcmtech, Darwin must be asleep. Please be more careful - you don't get that many chances.
 
Use enamelled wire.

Get some enameled magnet wire for a start, a good source of this is an old motor or transformer.
 
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