Re: NR SSTC

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Shaun Epp" <scepp-at-shaw.ca> 

Hello Steve,

The Plasmasonic 2 board is built just the way it was spec'd out, With the
MOSFET transistors that Dan used for the design.  The "CW" in the post name
I guess isn't right because I'm actually running it on half wave recitified
input power, not CW which would require filtered DC.  The "NR" is right,
"Near Resonance" for the primary ciruit which includes the H bridge and the
primary coil.

I  bypassed the on board capacitors, the ones between the H-bridge output 
and the "output + " screw terminal. Directly behind the output + screw 
terminal, beside the "HV IN -"  is 3
plated though holes, I soldered a buss wire  there (because that is before 
the series capacitors) and wrapped it around the screw terminal.

The Primary is 13 turns of 10 gauge solid wire, insulated on a 6.35 inch 
pipe form.
I varied the coupling my moving it up or down from level position.  Then 
retune.

BTW:  this is NOT the optimum size of coil to get good output on this SSTC,
but does allow me to do partial (near) resonance.  Before I was using 5.25
inch for the primary form until it flashed over.  The secondary is 4.25 inch
by 23 inch with 26 guage wire wrapped around it.  There is about 1300 turns
of wire on it insulated with polyurethane, inside, on the form and 12 layers
on the coil.  The top load I'm presently using is 12 inch outside diameter
toroid by 3 inch minor diameter.  From Information Unlimited.

The capacitor I used originally was a Glassmike like cap and it blew up. 
Now I'm using
my MMC which used Geek Capacitors used for my spark gap coil, It was my luck
that the value I needed of capacitance for partial resonance was the value
of my MMC.  The MMC consists of 0.15uF 2kv caps,  14 in series and that in
parallel with another 14 in series.  for a total capacitance of 0.0212 uF at
28 Kv.

I used a 120 V to 240 V step up transformer to power the H-bridge on the
board.  This transformer I pulled out of a radio therapy machine a couple of
years ago.  I connected it to the half wave recified input on the board, 
there are two series recifier diodes on the board for this.

I used a 20 amp variac to drive the step up transformer.  The step up
transformer isn't big enough to handle the currents I was drawing, so I'm
shure the output voltage was sagging, I didn't have time for measurements, I
started doing this at 2:00 am on a sleepless night.

I just realized as I was writing this that I might have been saturating 
that step up
transformer and that probably caused it to draw even more current!.  I have
another transformer,  a 120 to 120 - 140 volt isolation transformer.  It
came out of an argon laser.  I could wire it up as a voltage doubling 
transformer.  I'll try that In a day or two.

The step up transformer you might not need, it depends on how close to
resonance you are with your capacitor and primary coil and coupling.

Shaun Epp

BTW:  this message was cut and pasted from another message I sent to 
another coiler.

----- Original Message ----- From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, September 06, 2004 3:35 PM
Subject: Re: NR- CW- SSTC


>Original poster: "Steve Ward" <steve.ward-at-gmail-dot-com>
>Shaun,
>
>This sounds quite interesting and there have been at least 1 other
>person that i know of that did about the same thing.  Richie Burnett
>did a test like this once and i inquired about it.  He told me that
>you need an extremely tough capacitor to handle the very high RMS
>currents and at those frequencies, its rough.  He claimed about 32"
>sparks from a rather small secondary coil.  I, of course, was
>interested immediately and did experiment a little bit, but didnt get
>too far yet (perhaps my lashup was just a bit too sloppy ;-)).
>
>So is there any chance of getting any pics?  Dont have a friend with a
>digital camera?
>
>I guess i will just have to try it again on my own and get some pics ;-).
>
>One thing im wondering about is, what size toroid are you using?
>
>Steve
>
>
>On Mon, 06 Sep 2004 12:56:38 -0600, Tesla list <tesla-at-pupman-dot-com> wrote:
> > Original poster: "Shaun Epp" <scepp-at-shaw.ca>
> >
> > Well I tried something new   ; - )      I have a Plasmasonic 2 board > from
> > Dan and I did a partial series resonance on the primary.  I blew a
> > capacitor in the making of this and popped two fuses, which I soldered a
> > wire across (bad me!), popped the breaker on the power bar several 
> times > (I
> > plugged in direct after this) , and them the apartment 15 amp circuit
> > breaker a few times.  I put 240 Vac into the board with a step up
> > transformer, on half wave rectified to the H bridge.
> >
> > Resonance is suppose to be 0.015 uF according to WinTesla for my primary
> > and my MMC bank for my SGTC (which uses the same secondary and base) > just
> > happens to near resonant with my primary, It's 0.0212 uF.  Before 
> using > my
> > MMC bank I connected a 0.02 uF 10 Kv cap that I had in my collection. > It
> > worked at first, but then the glass cracked ,(the capacitor was very > 
> hot!)
> > and the capacitor separated.   Oops, I  guess it couldn't handle the > 
> power.
> >
> > Then I had fun with fuses and breakers.  Whee!  I can run it at about > 95V
> > input to the voltage doubling transformer before popping the circuit
> > breaker.  This set up gives fierce arcs and lightening like discharges
> > about 2 1/2 feet maybe longer.  It crackles when you draw an arc.
> >
> > I wish I had a digital camera
> >
> > Shaun Epp
> >
> > Tesla coiling in Central Canada
> > Winnipeg, home of the worst summer on record, comparable to Syberia
> >
> >