Re: Archived - European Fusor
Posted: Fri Sep 15, 2017 7:03 am
Why are you reluctant to place that transformer under oil? It would certainly be safer - both for you and the x-former! Especially if you intend to get up to 40 kV; above 25 kV electrical items get flaky (they can short to places/distances that normally one would not guess) and oil can provide a lot of safety margin in any system. The oil also allows less chance to have the high voltage jump to something that you are near or touching that would normally be safe ... .
Those diodes look extremely under rated for any significant current (I use 1 amp, 20 kV diodes (two in series, of course) and these costed me $2 each.)
Your chamber and high voltage feed-thru are impressive.
I see in the image those diodes are shorting to the mounting plate (wood?) You need to make a proper mount and seriously consider placing the diodes under oil (besides electrical isolation, provides improved cooling.) I mount my diodes on a plexiglass plate. I use ceramic stand offs to hold the plate up (to increase insulation) in a plastic tub that I fill with oil. The diode assembles lift out easily. Besides cooling the oil makes corona issues go away. I also save money because the wiring between diodes is just normal low voltage wire (110 v stuff); I only use the expensive 40 kV stuff outside the oil.
I use inexpensive synthetic motor oil (a research paper on dielectric properties showed that this oil was equal/superior for these applications so I decided to try it) and it works extremely well up to 60 kV (so far, max voltage I have tested to date.)
Those diodes look extremely under rated for any significant current (I use 1 amp, 20 kV diodes (two in series, of course) and these costed me $2 each.)
Your chamber and high voltage feed-thru are impressive.
I see in the image those diodes are shorting to the mounting plate (wood?) You need to make a proper mount and seriously consider placing the diodes under oil (besides electrical isolation, provides improved cooling.) I mount my diodes on a plexiglass plate. I use ceramic stand offs to hold the plate up (to increase insulation) in a plastic tub that I fill with oil. The diode assembles lift out easily. Besides cooling the oil makes corona issues go away. I also save money because the wiring between diodes is just normal low voltage wire (110 v stuff); I only use the expensive 40 kV stuff outside the oil.
I use inexpensive synthetic motor oil (a research paper on dielectric properties showed that this oil was equal/superior for these applications so I decided to try it) and it works extremely well up to 60 kV (so far, max voltage I have tested to date.)