# Electrical Resistance/Induction Heating Project

Discussion in 'The Projects Forum' started by RickH, Dec 10, 2010.

1. ### RickH Thread Starter New Member

Dec 10, 2010
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0
I am currently thinking about making a small melting pot capable of up too 2000 F. This gives me the ability to melt copper. I want to do a cross of Resistance heating and induction heating with Nichrome-60 Wire. I would have a S.S. Pot with a ceramic lid about 6" in Diamiter and 6" deep. It would be low Frequncy but that will be decided by the range of Resonance and capacitor size needed in the Tank circuit. The lower the frequency the deeper the feild penetration.

I have the Resistance per feet table per gauge of wire
I have calculated the Resistance per turn
I am not sure how to calculate the inductance per turn though. Its not an air core and I am not sure how many turns I will use.

So to get a Resonant Frequency I need the inductance, Inductor Resistance, and the Capacitance of the tank circuit.

I need this before I order the wire due to the gauge and length for the coil design. any suggestions?

2. ### nerdegutta Moderator

Dec 15, 2009
2,504
778
Be careful! Could be awful hot.

3. ### RickH Thread Starter New Member

Dec 10, 2010
21
0
Yup, thats kind of the point. I used to be a Feild tech for Raydine Corp tuneing RF units and left due to the danger of RF induction heaters. I don't like playing with water and 600VDC at the same time.

4. ### wayneh Expert

Sep 9, 2010
11,931
2,862
Are you familiar with the Wheeler formula? It's for estimating the inductance of a "solenoid" coil; layers of windings around a cylindrical core. But you'll need to estimate the magnetic permeability of your core for the formula to be useful. I guess the core will be mostly occupied by the copper you're melting? You should be able to find the permeability of copper. The SS pot will likely have a higher permeability but will occupy a small fraction of the cross section.

5. ### RickH Thread Starter New Member

Dec 10, 2010
21
0
Yes I found a spreadsheet on this forum, it was in a different Category

http://forum.allaboutcircuits.com/showthread.php?t=46448&highlight=inductance

I have compared it to some known setups and it seams to get really close. I'm gona order some wire and see how close it gets me even if I cant get below 1kHz its good enough for aluminum at low voltages and DC.

The 2 main advantages I am looking for is the EMF mixing the product and the increased efficiency. The drawbacks of pure induction heating are you need to cool the coil with water and you need to insulate the coil with space and a barrier as the coil would be copper also.

The key for me is getting a coil with enough L to reduce my C for a resonable Frequency in the range of 100-1000Hz is my goal. Its just an idea though as I already do this with a gas furnace.