[Home][2014 Index] Re: [TCML] Submerged diode strings hold off distance (transfomer oil) [Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Submerged diode strings hold off distance (transfomer oil)

Hi Jim,

I don't think it's a good idea to mount the rectifiers inside the tank. It's definetly not necessary to imerse them in oil neither for insulation nor cooling purposes. Another reason is: Maybe you will kill some rectifiers probably during some initial tests so do you really want to pull out the transformer everytime just for replacing dead diodes?


----- Original Message ----- From: "Jim Mora" <wavetuner@xxxxxxxxx>
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Sent: Friday, August 22, 2014 6:54 AM
Subject: [TCML] Submerged diode strings hold off distance (transfomer oil)

Hello Group,

Since I ordered and tested my Raytheon transformer fluid with a new Dexsil
40ppm test kit (available Forestry Supplies), I was pleased and bit
surprised that it is well below the 40ppm PCB limit, in fact near the
deepest purple on the lowest end of the test kit scale. It must have been
maintained for duty and flushed several cycles as was evident when I opened
it. It was military and under tagged FAA auspice after all.

Therefore, I have reconsidered my design a bit to mount the rectifiers
inside the tank. I removed the tall 12" horns for more space. And I seem to have ample room to mount my 6 pulse diodes strings recognizing there will be
six pulse 12KV dc + to - to hold off at the ends. The strings (3) will be
mounted horizontally as a stack and spaced to hold off the stress ~ 5KVac
(H1,2,3 will go directly to the rectifiers at the isolated centers) and the
ends (+,- 11KV) to any target. All 3 stacks will be joined at the ends for
plus and minus 6 pulse DC. Doing this frees up my three HV horns on the top.
One will connect to negative the middle horn will connect to the internal
positive and deque diode junction. And the other side the farthest one will be dequed downstream positive to go to the external Charge Inductor. I will
paint the base clamps Black, Yellow, and Red. Black is misleading as it is
well below ground potential (2 HV leads will exit). I will probably ground
the inductor tank and transformer together and may use 2 x-ray cables coax
case grounded at the transformer and strip 12" or so off out at the spark
gap. This has been an ongoing debate on the list unless it has been resolved
in my absence.

This gives me the option to experiment on top with different + to adjacent
minus storage capacitance (stiffening if needed) and ripple suppression and
a serious reminder to discharge a lethal, hidden energy source (it would
have bleeder but time is an issue after T1). Hopefully such a cap will not
be needed, but I like this external simple freedom of selection.

Having said all that, and if you stayed with me (thank you), how far apart
should the stacks be spaced to prevent flashover, and from other targets
like the HV coils and grounded case parts. I would mount them equal distance
in the center of the open space. I am more curious about the diode stack
spacing. I don't have a lot of experience with real transformer oil and its
dielectric strength.

Before the transformer reconfiguration there was 24KV for Raytheon engineers
to contend with and it was crowded in there!

Thanks Much,
Jim Mora

Ha ha, I am beginning to wish I sold this as a serious retro horror movie
prop or to the steam punk affectionaire. I do have (7) NOS JAN 8020
rectifiers in original packing (40KV peak inverse) and vintage EF Johnsons
sockets that will be for sale. The filaments are thoriated tungsten and glow pure white and instant on. Definitely old Frankenstein stuff! Those old >12"
white ceramic horns and bases will be on the block too as will the hefty
highly isolated 5V, 36 amp Filament transformer and maybe the 24KV 150H
filter choke. It has been interesting working on something older than I am
in great condition. This kind of device lends itself pretty well to EMP and was old school nuclear hardening. Forget about modern cars! It would be cock
roaches and old diesel trucks still going ;-^)

Tesla mailing list

Tesla mailing list