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Re: An Idea for a DC coil...



Original poster: "Kevin Ottalini by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ottalini-at-mindspring-dot-com>

Matt:
        You can probably do this several ways, but for DC coils,
it would NOT be good to try to run in sync with the secondary
resonance like a VTTC (not likely feasible with such a simple
design).  I doubt that you could run a disruptive coil at 50kHz
(or higher) ... just think of the power this would take!

Rather, an async 555 timer to drive the triggered gap or a traditional
async rotary gap would give the best effect and control ... be sure
to be able to change the frequency on the 555 from a few Hz to
about 1kHz.  If the 555 circuit proves to be too delicate, just build
an async rotary ... quite easy to do and pretty  inexpensive (no
tricky timing or adjustments).

The DC charging circuit would charge up the tank cap and the async
trigger (whatever source) would discharge it, the complete cycle then
needs to wait until your supply (whatever it's power) has recharged
the tank cap. 12KVDC should be dandy.  You shouldn't need any AC
side current limiting ... just a variac (30amps -at- 120V).

Be sure to add a series resistor or inductor between the rectifier and
tank cap to limit the surge current, or you'll blow diodes.

Static gaps would not be my first choice for a DCTC since I found a
traditional static gap gave very poor performance with DC, but I've
never tried a triggered gap ... might be interesting!

One thing ... you will need to put lots of protection and bypass on the
555 timer circuit.

Here is a link to my "starter" web page for DC Tesla coils ... just a
couple of pics and a schematic with ASRG:
http://www.mindspring-dot-com/~ottalini/DC%20Driven%20Tesla%20Coil.htm

I'll be updating it over the next week or so with lots of detail and pics
(unless I run out of web space!).

Kevin

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, November 26, 2001 7:15 AM
Subject: An Idea for a DC coil...


> Original poster: "Matt Shayka by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<lightningcreator-at-hotmail-dot-com>
>
> Hi all,
>
> Its been a while since I last posted, but I'm wondering about a
possibility
> for a DC coil. Here goes:
>
> What if(uh oh)a DC coil was rigged as a type of flyback? It would have a
> triggered gap, with a tap on the secondary or a small "extra" coil placed
> near the primary to pick up a pulse and trigger the gap to keep the cycle
> going. I have a feeling it will need something to initiate the first
firing
> of the gap. What do you think?
>
> I just finished my 12kV 200mA full wave bridge, and I plan on using it on
my
> 3" coil. It is currently running as an AC coil. But when I do convert I
> would like to experiment with this configuration. Has anybody tried this
> before?
>
> Thanks a lot,
>
> Matt Shayka