RE: statur report, stiff Poly Phase power supply

["Tesla list" <tesla@xxxxxxxxxx>]

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

Hello All,

Speaking of three phase and stiff power supplies, I thought you would like
to see the awesome power supply a purchased from another list member. It is
meant to be set up with a full wave rectification via (6) 8020 tubes. These
are to be replaced by 5 7500v 4A studded puck diodes each. The cascading
sockets will make for an interesting installation. The output Inductor is
150H and the voltage is 24KVdc, >.5amp. I have abandoned the resonant
charging idea as the poly voltage is suitably high. There is a Maxwell 1uf
40KV Cap on hand for filtering, but I'm not sure I want the added potential
for bleeder failure.

Presently, I'm on hold trying to find a bell housing for the Isuzu c201 2.0L
diesel to drive the 20KVA 3 phase gen head I bought on Ebay. The whole thing
will go on a trailer for demonstrations. I am asking Terry to post the
monstrous power supply, and schematic on the FTP server :-)

http://hot-streamer.com/temp/3Phase24KVDC.jpg

http://hot-streamer.com/temp/3Phase24KVDCschematic.jpg

Happy New Year
Jim Mora
Ojai, Ca. USA

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Friday, December 30, 2005 1:22 AM
To: tesla@xxxxxxxxxx
Subject: Re: statur report

Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>

Also going to need a "stiff" voltage source (aka unballasted
pig/unshunted mot/plate transformer/pt/etc). Nst's or any current
limited power source won't work very well and will throw off the
formulas on Ritchie's site at the least. I definitely wouldn't
recommend a DC resonant TC as a first project since they work best
with 3-phase (no multi-hundred-$ 200lb filter cap required).

Mike
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, December 27, 2005 8:17 PM
Subject: Re: statur report


>Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>
>
>Justin,
>
>To build a DC Tesla system "right", you are going to need
>some really BIG filter capacitors! I'm talking like quarter
>shrinker/can crusher sized caps! Then of course you'll al-
>so need to make sure that you have an adequate inductive
>reactor to keep all of the filter cap(s)' energy from trying to
>flood the spark gap and damaging or destroying the other
>tank circuit components. 0.1 uFd isn't nearly enough capacitance
>for a FILTER cap for even a small DC resonant Tesla coil sys-
>tem. Think 10's of uFds. Others that aren't as numerically
>challenged as myself can run the numbers and formulae for
>you.
>
>Having said all of that, it should be quite apparent that a
>typical AC Tesla system is considerably simpler to build and
>you get about the same performance per input power, so
>why bother with the extra labor, time and co$t of building
>a DC system unless you just want to meet the challenge?
>
>David
>
>----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
>To: <tesla@xxxxxxxxxx>
>Sent: Tuesday, December 27, 2005 1:18 PM
>Subject: statur report
>
>
>>Original poster: Just Justin <rocketfuel@xxxxxxxxxxxxx>
>>
>>Greetings,
>>
>>After a long period of research, I've finally started building my
>>first coil.  I must say, I was inspired by Malcolm's speed and so
>>I've set my sights on having something to show my friends on New
>>Year's Eve.  It will go well with the fireworks and flamethrowers.
>>
>>Anyway, my first source of good information was Richie Burnett's
>>wonderful site, which made me want to go straight for a DC
>>resonant system right away.  After thinking it over, I decided
>>that going DC resonant with my 12KV NST would require a very
>>high voltage tank cap and that I'd be better off using MOTs due
>>to their lower voltages.  In the meantime, I thought I'd try a
>>NST-bridge-filter caps DC system.  I built a propeller gap but
>>have had some alignment issues due to the way I constructed the
>>rotor, so I've shelved that and made a 6-segment (1"x6") copper
>>tube fan-blown gap.  Now if you're still reading I'm sure you're
>>probably going to say that there's no point in DC with the static
>>gap and I'm mostly convinced myself.
>>
>>However, when constructing the fan blown gap, I observed it as
>>NST + bridge, and again as NST + bridge + filter caps and saw very
>>different sparks.  Without the filter caps, the gap frequency was
>>very high, and the sparks were purple-orange, and they seemed to
>>persist as the fan blew them to the far side of the pipe.  With
>>the filter caps (0.1 uF) in place, the gap fired much less frequently
>>and the sparks were white and seemed "hotter".
>>
>>Of course this had me scratching my head.  My current theory is that
>>with AC and a static gap, the gap might break down several times during
>>the portion of the AC wave that is of a higher voltage than the gap
>>can withstand before breaking down.  With the NST + bridge only, this
>>would be more or less the same situation, but without the reversing
polarity.
>>With the addition of the filter caps though, I imagine that the filter
>>caps take a wee bit of time to 'fill' to the threshold voltage of the
>>gap, and when they do discharge, they add to the NST's current, leaving
the
>>cap's voltage after the spark somewhere between 0 and the gap
>>threshold voltage.
>>Once the plasma has been created, resistance goes down and so I'd imagine
>>they are somewhat depleted after the spark.  Then the cycle repeats.
>>I guess the question is how long does it take the filter caps to charge
>>to the gap voltage and is that longer than 1/120th of a second?
>>
>>My assumption is that any energy I might be storing in the filter caps
>>is just going to drain out through the spark gap, and therefore is
>>pretty much useless without the accompanying charging reactor and D-Q
>>diode of a full DC resonant charging system.  I still don't entirely
>>understand why the filter caps would not discharge through the spark
>>gap in a resonant system, except that possibly the charging reactor
>>limits the current out of the filter caps.
>>
>>I have a few specific questions that I'll post in seperate emails.
>>Thanks for reading and I'll appreciate any comments y'all might have
>>to offer.
>>
>>
>>Justin in Austin
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