Induction Heater Plans

[aflacglobal]

Good job Steve.

:wink:

 

[Anonymous]

Has anyone used an arc furnace? From what I have read they are easy to build and will melt anything. I even read in an old science experiment book of building one with the carbon rods from batteries, suitable fire brick, and a 100 w light bulb to controls the amp draw. That seemed real easy to build as it was for 9th graders.

Jim

 

[aflacglobal]

http://www.jackroeusa.com/Cinema-carbons.html

 

[Lou]

http://sciencemadness.org/talk/viewthread.php?tid=9793

is an arc furnace.

Theo Gray has a nice one he made as well.
see www.theodoregray.com



My friend Tim has also built his own induction furnace which works.

Video is available on his website:

http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat7.html


I look forward to hearing your results Steve!!

 

[Noxx]

I'm not able to locate any of the Inductors and Transformers parts.
Where can I get them ?

Thanks

Oh and I can't wait to see your setup :lol:

 

[lazersteve]

Noxx,

A couple of the inductors are homemade. I'll can show you how they are made.

The work coil (L1) is merely 4 turns of 1/4 - 3/8" copper tubing.

The matching coil (L2) is a bifilar wound coil of 7 turns of 10 AWG insulated wire on a flat spool air core form.

The feedback coil (L3) is 50 turns of insulated 14 AWG stranded wire wrapped on 1/2 of an old flyback core (C-Core) and hung from the work coil hot side via a 1/4 copper braid the ends of which are soldered to the work coil spaced at 1". The feedback coil gets zip tied to the resistive divider (braid) to provide feedback coupling from the work coil.

The 1:500 current transformer (T1) is a store bought item. I'm waiting on mine to arrive. I bought 10 of them if you need one we can work something out.

The 12 Vac 1 A supply transform is a standard Radio shack part as listed in the parts list.

As my unit takes shape I'll be posting photos.

Steve

 

[Noxx]

Ok thanks for the precisions...

I found the radioshack part... The part # is 273-1352

Don't add the letter «A» as stated in the schema.

 

[Noxx]

I've got an idea.

One could use Kaowool (or similar) to isolate the heat generated by the metal in fusion. This way, the copper pipe will not get that hot (a way from melting point), the heating will be faster and the melted metal will stay hot for much longer.

That's just my two cents.

And, is it possible to use a graphite crucible in this setup ?

Thanks

 

[Platdigger]

Graphite yes.
The copper tubing is water cooled. But the insulation couldn't hurt.

 

[Anonymous]

I think the copper may be getting hot from the amperage it is carrying and since it does not have a counter to self inductance.

Jim

 

[Lou]

Ah, it seems you did not watch that video my friend made of his induction furnace. It is lined with kaowool that I provided to him. You need kaowool if you want to melt and hold metals as a liquid.

Graphite crucibles work well.

 

[lazersteve]

All,

I finished the overall construction of the power and driver circuits today. I'm waiting on the 200 Kvar capacitors and a few more components for the work coil assembly. When they arrive I'll complete the unit and run some melting tests.

Here's the way the cabinet looks right now:

[img:538:1828]http://www.goldrecovery.us/images/induction_overall.jpg[/img]

Be sure to click on the image to see the closeup view.

Steve

 

[Noxx]

That's great (you did it fast too)
Do you think this won't generate too much heat ?

 

[Anonymous]

Steve you are very talented.

Jim

 

[lazersteve]

Noxx,

I plan on routing the copper tubing carrying the water over the heat sinks and attaching it with some copper clamps to keep the transistors cool. Everything else (the low voltage stuff) shouldn't generate much, if any heat.

I'm also planning on a few well placed miniature fans. Remember the rig you see in the photo is not completed.

Steve

 

[Irons]

I think the copper may be getting hot from the amperage it is carrying and since it does not have a counter to self inductance.

Jim

Ohm's Law strikes again. There are also eddy currents in the copper that generate heat. RF doesn't behave as nicely as DC. Then there is radiant heating from the melting metal in the crucible.

There's always using Silver tubing . A heavy Silver plate might help .8)

 

[Platdigger]

Irons, they use copper for this ....all the time. It is the "only" thing I have ever heard of being used for indution heating in fact.
Randy

 

[Absolutsecurity]

NICE WORK Steve!!!!!!!!

That looks like some top notch work!

Would you have any interest in making a working unit or kit for sale?

Just a thought - I know I would be interested and others might be as well!

A kit would be nice - then all the parts would be there and it would just be like the 1000 other projects that I cant get time to complete around here!! LOL!

Glynn

 

[Irons]

Irons, they use copper for this ....all the time. It is the "only" thing I have ever heard of being used for indution heating in fact.
Randy

No doubt copper is used. I just brought up Silver because it has a lower resistance than Copper.

If they were both the same cost, silver might be a better choice. It would make a more efficient tank circuit. The choice in capacitors would also make a difference.

 

[lazersteve]

Irons,

The tank caps are the most expensive part of this project. I got two of them shipped for a cool $249.

Steve