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

[Andrew Webster <andrew600rr@xxxxxxxxx>]

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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