Induction Heating

[HeXx]

Hello,
I have been reading allot lately about induction heating, and from what i understood is that it works with an alternating current passing trough a coil making the part being heated magnetic. I live in Europe so i already got an alternating current directly from the plug. Its 220 Volt 60 Hz.
For induction heating to work if i am not mistaken we need a much higher frequency at around 20-50khz. How can I make the 220V 60hz AC work at 20-50khz?
AC current from the plug works with a wave of Vmin=0 Vmax=220 i think.
For a induction heater to work would it have to be Vmin=-220 and Vmax=220?

Thank you.

[kubeek]

No and no. Mains AC voltage of a 220V line swings between -310 and +310V peak.
For an induction heater, the voltage depends on the coil you use and the required power. The high frequency is needed because metals have greater magnetic losses at such frequencies so they heat up more easily, and also because the size of the inductor and capacitor needed for 50Hz resonance would be huge and impractical.

[HeXx]

Thank you for your answer.
So can you help me with a circuit design that would allow the use of the house socket power cord and that would change it to the appropriate voltage/amperage/frequency to be used on a 8 turn 2cm diameter copper tube with the coil inside diameter of 15cm.
This is for a furnace.

Thank you.

[kubeek]

For example here http://danyk.wz.cz/induk3_en.html
Try googling for induction heater schematic, it will get you lots of other pages with different designs.

[HeXx]

Thank you very much for your reply.
I'm going to try to proceed with this project using that same circuit.
I would also like some opinions on what could be improved on it.
Im also woried about that 200$ capacitor at the power supply. It would be great to have a cheaper one...

Going to start making it on a simulator and analyse it.