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3 Phase Full rectification, doide protection, HV Inductor needed, advise urged.!



Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hello Group,

I am getting antsy to power up my 3 phase DC coil PS. The PS is from
Raytheon, Nikie era. It puts out 24KV DC. I think I posted a picture of the
beast once. Bert Hickman called it "Knurly", (California speak) and it is!

In its former Cold War Radar/tracking configuration, it used (6) 8020 vacuum
tubes for 6 pulse rectification. It has a 150 H inductor on the output which
does not play well by way of Richie's Burnett's equations. If my math was
not wrong, I would have a max 180 BPS (too small) and .4uf cap (too big). A
more ideal inductance would be say 75H so two of these in parallel or a
smaller one would work.

I don't know if there is any value in DC reasonance charing or just brute
force. The design is cool. The tube insulators step up to longer insulators
namely 4" to 10" with the anode caps.

Anyway, most tube suppliers suggest going to solid state diodes which I plan
to do. Where's the beef,... getting to that? I have (36) HDb7.5 puck, stud
diodes which are 7500v 1.4 amp rated. I would use 6 per leg (delta) wye
input.

So here are the questions:

1. Is there any point in resonance charging or for that matter can it be
avoided in some form?

2. What should be across the individual rectifiers in the strings to add
failure prevention and equalization?

3. Shall I bother with a de-queing diode string? (6 more).

4. I have 2 Maxwell 2uf/15kv Filter caps which I am considering placing
across the de-queing diodes inputs in series if such are used. Is that worth
the otherwise massive smoothing of the Inductor? And since the circuit, as
it seems to me, is getting Z complex, what effect does this have on the
filter or maybe charge inductor, or the Primary Cap for that matter?

I plan to pull the top off and make a new steel plate. The filament
transformer should be useful/desireable to our 833a/c tubers! 5v x 4, HV
standoff!

Lastly, Since this beast has a 208 x 4 wire (neutral)input and the HV
transformer is grounder, shall the negative output (delta) stay isolated or
can in too be grounded? More than a mouthful! Any suggestion welcome.

Thanks,
Jim Mora