Fusor Forums

I’ve just assembled a HV power supply for demo fusor/general plasma experiments. This is 5kV supply based on the breakdown tester transformer. I’ll post the details when I’ll do the load measurements, so I can report the detailed performance.


The small 5kV supply under construction. This is simple variable auto transformer - step up transformer - full bridge rectifier setup.

After having some hands on experience with HV supply building and looking for potential fusion capable supplies I started thinking about building one. As I’m rather into simple heavy metal - thick wire solutions rather than high frequency - semiconductor - switching solutions I’ve calculated a step up transformer.
Fortunately I’ve bunch of “U” shaped laminated cores RZC50/140/35. Assuming output of 16mA at 22kV double set of those cores (that is four “Us”) should have enough cross section (22.9 cm2). I’m thinking on putting the cores side by side forming the “8” shape, single primary winging on the central “pilar” and two secondaries on the the side pilars connected in series:



I’m planning winding the secondaries in the pancake configuration like it was used in the induction coils, insulated with electrotechnical paper and put the whole thing under oil. I would like to hear from the experienced coil builders if it makes sense, and what are the pitfalls here?

I have had a monster ion pump controller in the 2KW range in one of my sheds for 20 years and it has a huge xfrmr of that type in it. doubling, quadrupling, sextupling such a thing would be formidable and might prove ineffective and dangerous due to the capacitor storage needed to make it happen to advantage.

Richard Hull

Unfortunately I don’t have even single shed full of HV power supplies, so probably I will end winding my own transformer. Regarding the voltage multiplying - I’m not planing any. I hope that magnetic assistance/ion sources will compensate for the low end performance of the planned PSU. And in the worst case I will wind another, bigger transformer (or cascade two smaller transformers) with the help of gained experience. I don’t want to start with winding a 40kV monster - I prefer gradual steps and to gather knowledge from them.