Hi Jim,
Yes, that's the route that I would take if I were in your shoes, too. :`) I once had about 20 kJ worth of energy storage caps
(2 ea. 10 kV, 100 uFd units, and one ea. 10 kV, 198 uFd unit) paralleled together to do a bit of can crushing and quarter
shrinking. I can tell you that you must have a containment vessel that's built to bomb shelter bunker specs to be able to do
the quarter shrinking thing even half-way safely! The work coil literally shatters into shrapnel at supersonic velocities when
you engage the current from your charged cap to the work coil!! Also, you must have some real "humongonoid" (thanks
for a new term, Carl) ;^) contacts for making that connection if you expect them to last for more than one cycle :^) And as
far as can crushing, 20 kJ is really overkill for that and the so-called permanent coil for this purpose will fly apart within a
couple of shots! Of course it was fun to watch an aluminum soda pop can be literally ripped in half by shear electromagnetic
forces, though ;^) I ended up selling off my huge caps, as I, like you, felt the cobra charming analogy when messing with these
beast!
David
On Tuesday, June 24, 2014 1:30 PM, Jim Mora <wavetuner@xxxxxxxxx> wrote:
Thanks Carl and David,
I have all the stuff to make a 12" Pig coil and just made a new rotary more
geared to that supply. I have two giant 50KV 8uf capacitors for exploding
piano wire. Frankly, I find them a little like snake charming a cobra with
no anti-venom to fall back on. When the power is off, I like the HV to
return to a safe zone in a reasonable time without huge power dissipation.
Removing the energy from such caps is dangerous and intimidating to me. And
they have a tendency to assure my neighbors that guy is truly nuts ;-^)
I guess I'll pursue the path of least resistance and expense for now. The
12" form has been in my closet far too long!
I also will pull the Raytheon 3P out of the tank to see how it ticks but put
resonance charging on the back burner for now.
Thanks for helping me prioritize.
Jim Mora
-----Original Message-----
From: Carl [mailto:cn8@xxxxxxx]
Sent: Tuesday, June 24, 2014 9:11 AM
To: David; Jim Mora
Cc: Tesla Coil Mailing List
Subject: Re: [TCML] Resonate charging versus brute force.
Hey---
The only real advantage to a resonant system is if you have a power supply
whose voltage is too low. As David says, the big disadvantage (besides the
cost) is the humongonoid storage capacitor, which has to be about 5x the
energy storage of the "chargee" cap to get much advantage. Another approach
is to charge the primary cap through a full-wave bridge. The main advantage
of this is that you can charge a really big cap from a small transformer,
and avoid discharging the cap on the falling half-cycle.
(Can you believe that "humongonoid" isn't in Spellcheck?
---Carl
-----Original Message-----
From: David
Sent: Tuesday, June 24, 2014 8:29 AM
To: Jim Mora
Cc: Tesla Coil Mailing List
Subject: Re: [TCML] Resonate charging versus brute force.
Hi Jim,
Well, I have the experience with the plain ole asynchronous rotary driven,
raw AC from a 10 KVA, 14.4 kV pig. I have at times entertained the idea of
the converting my "big pig" Green Monster coil over to a DC res system, but
the substantial cost and increase of complexity to accomplish this has kept
me ON the launching pad from this project ;-) I just don't fancy the idea of
having to add a huge storage cap of several, if not 10's of uFds that can
withstand the full primary voltage of the system (huge and dangerous), plus
the huge multi-Henry charging choke(s), not to mention the appropriately
rated diodes - seems that I would be pretty near buying my current system
all over again :-/
With adequate ballasting, I am able to get plenty of "raw power" from my
simple pig, asynchronous rotary driven system, though. Plenty of fat and
very bright, 11 to 13 foot discharges! ;-) Of course, I'm told that once you
go DRSSTC, you'll never go back to SG coiling ;-) and there have certainly
been some quantum leaps in the development of SS coiling in the past decade,
but I just can't seem to get together the patience or the funds to "start
all over again" ;-)
David Rieben
Sent from my iPhone
> On Jun 24, 2014, at 8:36 AM, "Jim Mora" <wavetuner@xxxxxxxxx> wrote:
>
> Hello Group,
>
>
>
> I am wondering what experience people have had in DC resonance charging
> versus say 10KW pig powered and variable inductively ballasted of like
> order
> with synchronous and higher speed asynchronous rotary gaps. That of coarse
> is a huge set of topics, but general experience would be of practical use.
>
>
>
> It is my intention to try all three over time as I am sure many on this
> list
> have done. What is the practical best "bang for buck" and considerable
> effort. Please remember to reply to all even if you are flaming me ;-^)
>
>
>
> Thanks Much,
>
> Jim Mora
>
>
>
> While this old school technology is nothing like present SS and modulated
> coils, it is still awesome. I guess this is more a discussion of elegance
> versus raw power fairly well tuned.
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
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