They were demonstrating a 15KW water-cooled induction heater today at the Metal Museum. It heated a 1" steel rod red hot in seconds. I think it would work with a small crucible. All water-cooled internal components and water cooled copper coils. Direct import; about $900.00. Chiller is about $400.00 If I did forge work, I would definitely have one. If I had a 3-phase, 480 volt electric service, I would get a much larger one. .
Pretty cool! Hmmm, seems like you could make one of those attaching welding leads for the power source. Did I see that somewhere on the Internet? It's such a big place.
I’ve been dreaming about an induction furnace for quite a while. Very cheap to operate. BUT to melt 60 pounds of iron requires a huge monetary investment for the furnace plus you need to have industrial strength electrical service. Denis
It would not take large equipment. What you need is energy, and energy is easy to store with ceramic fiber blanket. I can see an airtight chamber with an induction coil which is large enough to raise the temperature of the charge 300F per hour. In ten hours you're ready to pour. You could even kick start it by loading a hot crucible but the point is you really don't have to melt it in five minutes in order to be successful. 60 pounds of iron, if my arithmetic is right, only takes 18,000 btu. If the crucible and insulation doubles that you need 36,000 btu. If coil cooling takes away another 36,000 btu you need 72,000 btu of electricity, or 72,000 btu/hr = 21 kw. If you do it over four hours that's a manageable 5 kw load, 25 amps at 220 volts. The question is do you need to melt quickly?
Sadly I'd rather burn motor oil. But I guess I could cast on rainy days like today. And warm the shop in the winter.
I may ask for some preliminary feasibility help on this on another forum. If this could be done it would be a huge boon for me. And if there are folks here with the electronics expertise to know how to put together the switching transistors etc necessary to feed adequate power into an induction heated of adequate size, please pipe up. Denis
I was thinking about powering it with a high frequency TIG welder although it may not take high frequency for melting. If you've got a TIG welder anyway. It's not going to be a big load for a 200 amp welder but sure have to stay under the 100% duty cycle. It does for surface hardening, the higher the frequency the lower the penetration for induction but I don't know that induction heating works well at 60 cycles.
The electric service size at my house is what stops me from buying one of these. And this unit probably does not have a line side reactor, and so could damage all the electronics in your house, as well as damage the utility company transformer (I have not verified whether it has a line side transformer or not). These units are readily available in the KW size that we would need, but those units are 480 volt, 3-phase. I heard of one guy who ran one off of a big diesel genset at 480 volt, and a big diesel genset may be cheaper than a new electric service (assuming they would install 480 volt at your house; they would not). Also in an industrial setting you would be setting a demand load, and so would pay for the demand every month whether you used the furnace or not. .
There are available 5Kw melting furnaces/power supplies intended to melt small amounts of iron, gold etc. these are coupled to a correspondingly small induction coil. They run on 220 power with household circuit load levels. I am thinking along the lines of OIF’s post above where the idea would be to run a furnace at only 5 Kw and accept longer melt times. How safely made those units are with respect to other appliances sharing their supply circuitry I have no idea. Like this: Your/others’ comments? Denis
