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Plastic Insulated Wire Usable For Coil In A Coil Gun?

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LAN_403

The Zander

Sat Apr 15 2006, 02:53AM

Registered Member #295 Joined: Tue Mar 07 2006, 06:59PM
Location:
Posts: 23

i does seem quick, but you are dissipating alot of power, and it was a purely theorectical calculation to demonstrate that given atmospheric heat dissipation, and perhapes slightly lower current (4000 rather than 6000) your 18AWG enameled wire should suffice, not to mention you eliminate the plastic insulation (which will fail at a lower temperature than the enamel, and you increase your magnetic flux density considerably).

-TheZander

Sulaiman

Sat Apr 15 2006, 06:56AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Since you need to use more than one switch/thyristor due to Peak current,
rather than using one thick wire or a few thinner wires per coil
you could make multiple coils with one thyristor per coil.

You could make each coil length similar to projectile length .... conventional multi-stage CG
OR
You could make each stage using coils of 1/2 (1/3, 1/4...) the length of the projectile
and use 2 (3, 4...) thyristors, with an adjustable delay per thyristor.
In other words, each stage (maybe only one stage) is made of a multi-stage accelerator.
I imagine less 'suckback' so possibly better efficiency.

Just an untried idea for you to ponder ;)
(If it works I name this Multi-Mini-Coil-Gun MMCG just for the sake of confusion)

P.S. You could treat each multi-coil stage as a single stage
and 'fire' all thyristors for one stage simultaneaously,
OR
Have precise variable delays per thyristor (monostable timers etc.)
OR
you could trigger the first thyristor per major-stage as required
and use a few turns of wire on each coil to trigger the thyristor of the next sub-stage
a resistor in series with the trigger coil and a capacitor across the gate to ground
could give a little delay per sub-stage.
e.g. 400V supply, 40-turn accelerating coil, 1-turn pickup-coil for about 10V trigger voltage.

FastMHz

Sat Apr 15 2006, 05:43PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

My induction launcher is feeding 3.5kj into 14awg coil with minimal heating after a shot - I don't think you need 10awg. I got the wire at www.bulkwire.com.

Electroholic

Sat Apr 15 2006, 06:08PM

Registered Member #191 Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720

A disk launcher coil? pancake right?
whats the total lenght of the wire?
whats the surface area?
coil gun coils have a lot more turns,
and have more layers.

If you are not planning to do more than 1 round every 5 min,
~14 awg is ok.

FastMHz

Sat Apr 15 2006, 10:05PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

Yes, dual layer pancake coil, with each layer paralleled...the coil is 3.5" in diameter using 14awg wire, so there isn't as much as in the average CG, which means the amps are even higher. I do have a few CGs made with the same wire and they can be fired about 3 times before needing a cooling period. The disc launcher can be fired every couple of minutes.

Quantum Singularity

Sun Apr 16 2006, 12:15AM

Registered Member #158 Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282

I myself would go ahead and try the plastic insulated wire. Its cheap, at worse your out about $1 and a half hours work (approximate of course). You will loose efficiency probably, so thats up to you and your goals, although I like to prototype stuff first and build a more refined final design later. I have built flat spiral coils for induction launchers like fast MHz and due to my budget at the time (poor college kid). They were #12awg and #8awg standard houshold wiring from Home Depot (probably a dollar or two worth of wire). I had a real blast launching stuff, it was way more powerful than I needed, and I didnt not have any means of calculating efficiency or reason too for that matter. On my next design I am going to use some #13 awg magnet wire since I got some locally at a motor repair shop. And hopefully I will have a chrono so I can measure speeds and calculate velocities.

evilgecko

Sun Apr 16 2006, 11:17PM

Registered Member #288 Joined: Mon Mar 06 2006, 07:52AM
Location: Palmerston North
Posts: 32

Yeah I'll give it a go. Dare to be different. iAlthough I'm building it because I find it interesting, I'm trying to incorporate it into a school science fair project as well. And using plastic insulated wire could put an spin on the whole joe average design.

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