Re: [TCML] Coil V1.0 Arc over between turns of secondary.

[DC Cox <resonance@xxxxxxxxxxxx>]

Sounds like it's way out of tune.

Use JAVATC to verify your complete design.  This powerful program will give
you answers and it's very fast and easy to use.  Free online.

Breakouts along sec could be bad wire (surplus perhaps with nicks in the
wire) or more probable over coupling of pri-sec.  If you provide more pri
sec details we can check this in JAVATC.
Dr. Resonance




On Thu, May 27, 2010 at 5:44 PM, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:

> Coil V1.0 ...  in debug mode.  <http://yfrog.com/5d24dj>
>
> Hello All.  My story continues.
>
> I fabricated a circular wooden platform out of 2 23" pine table tops (home
> depot), mounted the primary, the MMC, and the Terry filter each on different
> levels.  Then I made a larger platform upon which I mounted the NST, the
> line filter, and the spark gap assembly.  The spark gap is a static gap
> consisting of 2 tungsten rods (McMaster Carr) mounted in copper power panel
> lugs.  The lugs were positioned atop two ceramic standoffs.  I had to use
> nylon bolts to bolt them to the base, as when I used conductive bolts the
> capacitance between the two terminals with the wood as dielectric prevented
> any sparking.
>
>  I got a 115V squirrel cage fan (Howard Cyclohm) from Surplus of Nebraska
> and mounted it also on standoffs, mostly so that it would be the correct
> height to blow air through the spark gap.
>
> Now it was time to test the gap.  I had bought my NST through eBay.  It
> indeed had a GFI  - but for some reason  the GFI was busted, and it
> generated nice sparks.  I had made a quick jacob's ladder to verify the
> operation, but naturally, after making sparks for my spark gap, the GFI woke
> up and decided to start shutting things down.
>
> This, then, indicated surgery.  I managed to saw the rivets off the NST
> that were holding on the top.  To my glee, I saw the GFI circuitry was not
> potted, and I was able to simply yank it out (after removing the circuit
> breaker switch from the case).  Actually, this GFI was more than just a GFI
> - it had some internal smarts that would assess whether or not the thing was
> wired correctly, and so had some microprocessor circuitry along with the
> simple current sense.    After clipping all the wiring, I was able to simply
> reconnect the primary of the NST.  I put the top back on, replacing the
> rivets with small 6-32 bolts and nuts.  "Voila," as they say in France and
> parts of Canada.  My Franceformer was working again.
>
> Dan McCauley's book describes a procedure to measure the resonant frequency
> of the secondary + toroid, and then use that number to set the MMC+primary
> combination.  I was able to do that with a signal generator, an
> oscilloscope, and two LEDs.   Things were moving swimmingly.
>
> I adjusted the Spark Gap according to the notes here on the TCML.  Then I
> set the safety gaps on the Terry filter the same way.  I had built my wooden
> foundation so the power supply would be separate from the coil itself, but I
> rested one atop the other for the sake of my first light test, and I wired
> everything up.
>
> Now - it's time to mention that I had to perform some surgery on my
> secondary.  The only part of the coil that I did not make by hand (other
> than the electronic components and the toroid) was the secondary.  I bought
> that via eBay.  The problem I had with the secondary is that it did not
> follow the "rules" I had read in Dan's book, and also here on TCML.  That is
> - one should never have anything inside the core of the secondary.  The
> person I bought the secondary from suggested wiring both the toroid and the
> ground through the center of the coil, through holes one has in caps you
> place on the top and bottom of the secondary tube.
>
> I undid this.  He had drilled holes in the secondary tubing, and inserted
> the wire ends on the top and bottom.  I pulled these out, plugged the holes
> with epoxy.  I made plugs for the top and bottom from 1/2" thick sheets of
> gray PVC as Dan's book suggests, drilled holes and inserted 1/4"-20 nylon
> bolts, and I epoxied these to the ends of the secondary tube with the ends
> of the bolts exposed.   On the top I epoxied a disc of copper, and soldered
> the end of the secondary winding to that disc.  On the bottom, I soldered
> the end of the secondary wire to a small plate of copper I epoxied to the
> outer wall of the tube.
>
> Toroid went on the top - electrical connection made by touching the copper
> disc on top.  Ground connection to the bottom small plate.
>
> I mounted everything on the primary assembly, wired everything, and then
> connected the RF ground to a rod I pounded in outside in my wife's garden.
>
> Using a variac, I slowly increased the voltage.  Instantly, I saw where
> little arcs were forming.   I was able to solve most of these by tigthening
> bolts, resoldering certain connections where I had left rough ends, and
> ridding myself of inadvertent capacitors formed by having the lug connection
> to my MMC above the polycarbonate sheet in which the capacitors were
> mounted, and the eye grommet on the underside, shorted by the bolt that went
> between them (see picture).  This turned out to be a bad idea.  I put the
> eye and the lug on the same side of the sheet and those little coronal arcs
> went away.
>
> But alas - I was (and still am) getting corona break out from turns in the
> secondary,  and arcs between  turns of the secondary.  I have tried changing
> the tuning, but this doesn't change things.  I have tried to see if I had
> some spots of epoxy left over from my modification of the secondary, and I
> wiped down the secondary with alcohol.    It seems pretty clean.
>
> But when I turn up the variac, I get these breakouts on the secondary.
>  Changing the tuning eliminates the breakouts and arcs, but I think it does
> that simply because the tuning is wrecked and currents don't build up in the
> secondary.  In any case, I never see a corona or an arc from the breakout
> point I put on the toroid.
>
> Whew.  Thanks if you read along this far, and any advice you could lend
> would be much appreciated.
>
> Thanks,
>
> Joe
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla