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Re: [TCML] Odd VTTC Streamer Behavior
Actually that all looks pretty nice from what I can see in the
photo. I don't know if that loop of wire hanging would
make very much difference. Are you saying the loop was
part of the primary then it fell down?
When I spoke of hte size of the doubler cap, I wasn't
refering to the reduction in spark length you saw.
I was refering to the general problems you had at
high power with spark splitting.
I see too that you're using the high mounted grid
coil such as Cameron used. I also see that there seems
to be quite a few turns on teh primary. Either that
or it's rather thick wire. How many primary turns are
you using, and how many grid coil turns? What happens
if you use a much lower position for the grid coil?
If you gradually lower the grid coil, does the spark
length change gradually? Or does the spark vary
up and down depending on height? For example
if you lower the grid coil about 2" does it have much
effect? I'm thinking maybe you're taking advantage
of various phase conditions by using the high grid coil.
the high grid coil might be improving the sparks, making
them generally more sword-like.
John
-----Original Message-----
From: Phillip Slawinski <pslawinski@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Wed, 22 Oct 2008 8:53 pm
Subject: 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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