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Re: [TCML] Odd VTTC Streamer Behavior
Whoops, did I say nF? I meant uF. Cameron uses more than 2uF in his
system. However, like I've stated earlier I was getting 34" streamers at
one point, and I did not change the size of the doubler.
Here is a picture of the coil throwing off 34" sparks. Note the slack from
the unwound primary hanging off the right side of the enclosure. Mind you
this setup is somewhat ugly and hacked together! I'd like to get the coil
tuned out before I move it to a nice looking enclosure.
http://www.flickr.com/photos/pslawinski/2965044739/
Perhaps the uncoupled inductance have been signifigant in this case?
On Wed, Oct 22, 2008 at 16:52, <futuret@xxxxxxx> wrote:
> Well tube arcs without a plate lead choke/resistor can
> sometimes be subtle and not destructive, but are often
> destructive. It can be either way now that I think of it.
> It's much safer with the plate lead choke/resistor.
> Usually if you're using a level-shifter doubler type
> system, it's traditional to use about 2uF or more.
> You might not be getting all that much doubling
> action if you're only using 2nF. Did Cameron use
> the same series MOT with doubler system that you
> used? And did he get proper sword sparks up to
> 36"? If so, then you may want to verify that your
> system is set up the way his is. I never used series
> MOT's in a VTTC, so I have no experience with that.
>
> For my 36" sparks I used a pole pig for power, and for the 24"
> sparks I used a single MOT with level-shifter.
>
> John
>
>
>
> -----Original Message-----
> From: Phillip Slawinski <pslawinski@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Tue, 21 Oct 2008 10:47 pm
> Subject: Re: [TCML] Odd VTTC Streamer Behavior
>
>
>
>
>> Since you have a plate lead choke/resistor, the arcs will
>> appear subtle. Without the choke, the arcs would be
>> spectacular and possibly instantly destructive.
>>
>>
> I don't think I'm getting tube arcs. I use no choke, and no resistor on
> the
> plate lead, I like to live dangerously! So if like you say the arcs are
> instantly destructive without the choke then I haven't been getting them.
>
> On Tue, Oct 21, 2008 at 20:44, <futuret@xxxxxxx> wrote:
>
> Seems it's not a tube problem. If the cap is failing, it can
>> change the tuning, which can effect the forking.
>> But the forking effect could
>> be something else. I had a lot of trouble with spark
>> splitting on my small 4-250A coil which gave 20" sparks,
>> and on my (2) 833A coil which gave 24" sparks. I found
>> it to be sensitive to the type of power supply even.
>> For example if I used a 4450 volt plate transformer,
>> then the splitting occured. But if I used an MOT with
>> level shift, and the correct number of level shift caps,
>> then the splitting didn't occur.
>>
>>
> I use a 2nF 13000V oil-filled filter cap. It's huge and I hate it, it sure
> was cheap though at $10. Is it possible I could get better results with
> higher capacitance?
>
>
> But it split occasionally
>> anyway. It can be difficult to get longer and longer
>> sparks and continue to avoid the splitting. It may
>> help to lower the breakout point on top of the toroid
>> or something like that. The toroid affects the electrostatic
>> conditions in that area and may help to funnel the spark
>> straight up.
>>
>
>
> The tip of my breakout point is about 3" above the toroid. I'll have to
> try
> moving the toroid up or the breakout point down to see if that.
>
>
> I think the splitting has a lot to do with
>> how the spark originates at the breakout point as
>> it begins to grow at each burst. If it splits early
>> as it's forming, then it will stay split. The trick is
>> to get the spark to form without splitting. This
>> makes it sensitive to tuning and various adjustments also.
>> Did you try varying the main tank tuning some?
>>
>
>
> Yes, even added taps to my primary. I have L maxed right now, though I've
> added more L and the spark length does not increase, and it certainly does
> not help with the arc splitting. I tried adding more C today and after I
> tuned it out there was really no difference in the spark length, if
> anything
> it was slightly shorter.
>
>
>
>>
>> It may even be beneficial to use an MOT which
>> saturates, because the waveform distortion which
>> results can help to stop the splitting perhaps.
>> In any case, varying the number of level shift
>> caps may help.
>>
>> John
>>
>>
>> -----Original Message-----
>> From: Phillip Slawinski <pslawinski@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Tue, 21 Oct 2008 7:15 pm
>> Subject: Re: [TCML] Odd VTTC Streamer Behavior
>>
>>
>>
>> I just tried the 833A I have laying around. It was the same
>>
> situation as
>
>> with the Penta 833C. I also examined the inside of the C and
>>
> everything
>
>> looked perfect.
>>
>> Would the cap really cause the streamers to fork like that, and not
>>
> gain
>
>> any
>> length?
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