It runs at about 50KHz (not 50Hz), which is typical for these things. The power supply is DC, and under load is about 38V (while providing 10-20A). The operating frequency does not come from the power supply - it's the natural resonant frequency of the tuned circuit (tank) formed by the heater coil and capacitor bank. The switching transistors are in the ZVS (Zero Voltage Switching) configuration which is simple, and automatically adjusts to pump power into the tank at its resonant frequency. **Everything** gets very hot at this power level, so there is water cooling with a pump and reservoir, plus heatsinks and fans. The 2-3KW version I'm eventually aiming for (like that in the silver powder melting video) is quite different. It will run at high voltage (340VDC), and the drive circuit won't naturally seek the correct frequency, but must be controlled by some complex electronics to keep the tank in resonance. I'll probably use an embedded microcontroller to operate everything.
OK, now I get ya. Yes, I've seen those. It's cute, but mostly seems to be just a curiosity, except for those highly specialized applications referenced in your links pertaining to maintenance of high purity of some (non-precious) metals. Not very useful to me to have a kilo of molten silver floating in mid-air, and from what I understand, these also require massive power levels. I'll stick to just trying to melt silver and gold in a crucible, as per normal practice in the PM industry.
Now you know the right term to use From Engineering POV, Induction Coil are the way to go, not unless lack of technology. They are better cleaner precision methods for today market. Less wastage and cleaner product Compare to the torch, burner which will consume more energy and yet dirty products.
Yeah, I've seen some diy units online which use an arduino and others that use a phase locked loop to maintain the frequency. Any reason for using a bank of capacitors as opposed to a single large water cooled capacitor of equivalent rating to the bank. I mean seeing as you're already using water to cool the work coil and the heat sink(s)?
I'll be playing with both. An AVR-based board to provide PWM driver signals, and a PLL as feedback into the AVR Yes:- * Proper induction heater capacitors are very expensive. * I have heaps of these 220nF 630V caps, they cost me only a few cents each The bank uses 16 caps (less than a $1), so I'll probably never even bother with flared coil fittings, and just fit a new bank to each coil I make...
