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Re: [TCML] At a loss. No light on second coil



Hi Again Andrew,
     Not sure what to tell you, MOT stacks provide a lot of power, but they
are bad power arcers, because the voltage is low, so the gap spacing has to
be low (I got a sucker to work on mine, but never remotely well.)  The best
I can suggest is blow more air through it; actually no, I would also
suggest you cut your cap bank in half to 5 rows, this will aid with
quenching (even if it reduces your power level at that BPS range.)  Your
sucker gap might fare better under those conditions of lower current draw,
and if nothing else it will give you a new tuning range in case a
calculation is off, and the coil is "untunable" from a resonance
perspective.  If it helps, a smaller cap will require more primary coil, or
less secondary coil.  It is also possible due to the big cap and small
secondary, that your primary has too much inductance at 1 turn to be
tunable, cutting your bank in half should help us to see if that might be
the case.  As an experiment, you might try your old bottle caps again, just
keep run times short to take care of the heat?  This might help tell you if
you are not tunable in that config...  If that is the case, than this will
be the first coil I've ever seen where a secondaries size actually made it
in-operational, it is generally one of the least critical things in
reality...  Let us know what you decide, and how it works!

Scott Bogard.


On Wed, Mar 27, 2013 at 2:25 PM, Andrew Webster <andrew600rr@xxxxxxxxx>wrote:

> Thank you for your very detailed response Scott,
>
> I see your logic here and I have a few new things to try. With my
> rotary down, I have been using my 2 horn sucker gap (Very much like
> this one: http://www.flickr.com/photos/gomezaddams/1439374053/ ) It
> sounds as though it is firing but it may still be power arcing. Other
> then opening the gap more is there anything that I can do to help with
> this for testing? It is hooked up to a shop vac on full power.
>
> As for my cap, I did upgrade from the bottle cap to a nice MMC. 140x
> 942C's 10 rows of 14 for 108.7nF @ 28kV. I have hooked this up to my
> multimeter and it reads great without showing any loss due to a short
> and I have inspected it over and over again to make sure I was not
> missing anything. No signs of any damage to them either.
>
> I would assume based on what I have read from everyone's help here
> that I am power arcing. I will start rebuilding my rotary right away.
> I just need the parts and think Ill give the copper tungsten alloy a
> try as the brass was a puddle after just a few seconds. For the time
> being though I would like to get it up and running.
>
> Any advise on the sucker to help alleviate the power arc would be very
> welcomed. And here I was thinking I had this figured out after such
> great success with my first coil..
>
> Thanks again everyone!
>
> -Andrew
>
> On Tue, Mar 26, 2013 at 5:55 PM, Scott Bogard <sdbogard@xxxxxxxxx> wrote:
> > Hi Andrew,
> >      I wouldn't waste my time with the capacitors just yet, and here is
> > why...  MOT coils work great without them (I don't use them), so by
> adding
> > them you are not figuring out why the coil is not working, you are just
> > changing a variable which is likely not the problem (spark gap is firing
> so
> > power supply IS working to one extent or another) and introducing more
> > possible causes of failure.  If I had to guess I would say you are
> majorly
> > power arcing, I had the exact same problem with my first 4 MOT stack.  I
> > suspect you are also badly out of tune, both these things will cause
> > the symptoms you are experiencing, assuming you don't have a secondary
> > short or carbon trail, which seems to not be the case according to your
> > inspection.  As for your secondary being too small, I wouldn't fuss about
> > that too much, yeah your coil is a bit small for your power level, but it
> > is easy to dial back power until tuning is fixed.  If it were me, I would
> > do the "put a pole next to the top load and look for sparks" thing until
> > you get it tuned.  Don't be afraid of sparks spontaneously forming
> > regardless of power level, it isn't going to spontaneously start working
> > fantastic and kill you (unless your spark gap is terrible and not
> > quenched.)  I would also personally rebuild your rotary, that will rule
> out
> > power arcing (if the arc in the gap stretches, it is power arcing.)  It
> is
> > also possible a MMC cap shorted, and it is now impossible to tune in your
> > configuration, I've used a lot of homemade caps early on and that was
> > sometimes a problem.  What are your cap specks again?  Remember as your
> > voltage goes down, you need a bigger cap to maintain a healthy power
> > transfer rate; if your cap is too small, it will be impossible to tune
> from
> > a power draw standpoint, even if it is "in resonance."  It is also
> possible
> > one leg of your MOT stack is unhooked, but you said you drew sparks from
> > it, so I don't believe that to be the case this time.  Anyway when push
> > comes to shove, if you want to rule out the power supply, don't throw
> more
> > parts at it, take away parts, fall back to 2 MOTs, this would be more
> > prudent troubleshooting practice.  Once you are running a 2 pack, go from
> > there with tuning, and once it purrs, reintroduce the other MOTs, and
> feel
> > the power!  Just my recommendation, I wouldn't want you to spend 2 months
> > trying to figure it out like I did...
> >
> > Scott Bogard.
> >
> >
> > On Tue, Mar 26, 2013 at 1:51 PM, Andrew Webster <andrew600rr@xxxxxxxxx
> >wrote:
> >
> >> Thank you,
> >>
> >> I think that is my next step. Ill start with 5 MOCs per side in
> >> between the first and second MOTs on each leg (AKA Greg from Hot
> >> Streamer) and then go from there. I guess I was more of less wondering
> >> if it was possible to overwhelm your coil if the power was too high?
> >>
> >> No carbon
> >> Great grounding (8' copper rod buried straight down in semi-sandy moist
> >> soil)
> >> Primary, secondary, toroid were pulled from a working coil. Just much
> >> less power.
> >> Cap and gap are firing great. You cannot miss the sound of the gap
> >> snapping that hard.
> >>
> >> I have even run it in total darkness to see if I was arcing somewhere
> >> and didn't notice. Unless its on the back side somewhere I cannot find
> >> anything. Which is why I am so confused as to how I screwed this up so
> >> bad.
> >>
> >> My other thought was to lower the capacitance to see if it broadens
> >> the tuning. Maybe its just too tight?
> >>
> >> Ill setup with the MOCs and report back. Most likely this weekend. If
> >> anyone else has any ideas I would love to hear them.
> >>
> >> Thanks again all, it will be a great day to see this come to life.
> >>
> >> On Tue, Mar 26, 2013 at 1:07 PM, Atomic <atomicrox@xxxxxxxxx> wrote:
> >> > I'm no expert but I've seen MOT coils using MOCs as capacitive
> ballasts
> >> in
> >> > series with the HV side of the MOTs. Might want to try that out..
> >> >
> >> > On Tue, Mar 26, 2013 at 1:37 AM, Brandon Hendershot <
> >> > brandonhendershot@xxxxxxxxx> wrote:
> >> >
> >> >> I'll second that. If you're confident in your numbers and you've got
> >> that
> >> >> much raw power pumping into the coil without any output, then it
> seems
> >> to
> >> >> me like a power arc. Nice catch David.
> >> >>
> >> >> Brandon H.
> >> >>
> >> >> On Mar 25, 2013 5:51 PM, "David Dean" <deano@xxxxxxxxxxxxxxxx>
> wrote:
> >> >> >
> >> >> > On Monday, March 25, 2013 04:26:16 PM Andrew Webster wrote:
> >> >> > > So I built a 4 pack MOT
> >> >> > > stack and wired for 240. Center grounded and under oil. There is
> no
> >> >> > > ballast on this and I can draw some nasty sparks off of this.
> >> >> >
> >> >> > So your gap is not quenching, hence no sparks.
> >> >> >
> >> >> > >I am using a static sucker gap as I melted the brass off of the
> ARSG
> >> >> > >in seconds. The static gap is holding up better to the heat until
> I
> >> >> > >can get some tungsten.
> >> >> >
> >> >> > I probably should not say this, but:
> >> >> > You might try a 100 foot extension cord to act as a "resistive
> >> ballast"
> >> >> > keep run time short, as the extension cord will heat up, could
> melt,
> >> >> could start
> >> >> > a fire. Only a test :-D
> >> >> >
> >> >> > Or better, do a real ballast.
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