Re: [TCML] Odd VTTC Streamer Behavior

["Phillip Slawinski" <pslawinski@xxxxxxxxx>]

I ran it for quite a while today, and I think I made some progress towards
getting back to where it used to be.  It's hitting 31.5", and it's making a
thudding sound while doing so.  It does this while running just shy of
105V.  If I push it up to 115V or higher the sparks start to make a cracking
sound in addition the the thudding.  It's also at this point that the sparks
start to branch and become shorter.

I tried lowering grid resistance and it only results in shorter sparks, and
only marginally at that.  I'm a little wary to lower the resistance since
the accident that marked the end of the good performance I was getting from
the coil.  I kept turning down the resistance until the secondary flashed
through the silicone sealant and ruined my grid coil.  Of course, this was
an extreme case, and foolish at that.

I did move the grid coil down to increase the coupling a little and that
seemed to help.

On Mon, Oct 20, 2008 at 21:03, <futuret@xxxxxxx> wrote:

> The throaty popping sound may be a "bad" sound meaning
> the coil is not running just right.  Some component may be
> failing.  Or the staccato controller timing may have changed
> in some way.  The solid thud sound is good, other types
> of sounds can be bad.  Is it a raspy sound?  If so that's
> a sure sign something isn't right.  Maybe from the high
> power operation of the tubes, they became damaged.
> Or arcing may have been occuring in the tubes which
> can make a popping sound.  You can try reducing the
> grid resistance to see if it helps.  That tends to keep
> the voltages in the tube lower and may help.  But it
> will make the tubes run hotter of course.  But it may
> be helpful just as a quick test to get an idea of what's
> happening.
>
> John
>
>
> -----Original Message-----
> From: Phillip Slawinski <pslawinski@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Mon, 20 Oct 2008 6:51 pm
> Subject: Re: [TCML] Odd VTTC Streamer Behavior
>
>
>
> On Mon, Oct 20, 2008 at 17:13, <futuret@xxxxxxx> wrote:
>
>  This is a common problem with VTTC's in staccato mode
>> when producing the single sword-spark.  If the timing
>> of the staccato trigger signal is not quite right it can
>> contribute to this.  Also the type of power supply
>> can affect this (how many level shift caps, etc).
>> Various tuning, coupling, grid-feedback issues,
>> etc., seems to affect it also.
>>
>> It may help to sharpen
>> the breakout point, or raise or lower the breakout
>> point relative to the toroid, also.  The tip of your
>> breakout point may be burning and getting dull
>> and rounded.  Since the behavior seemed to occur
>> by itself, it may be due to the breakout point
>> rounding from burning over time.
>>
>
>
> John,
>
> I think you're right about this.  I had noticed the tip had become quite
> rounded and had attempted to to sharpen it, but I guess I just didn't
> sharpen it enough, and then to top it off I melted it with some CW runtime.
> I should get a tungsten breakout point, ha!
>
> I tried a sharpened piece of wire as the breakout point and it does seem to
> help quite a bit.  However, past 100V the discharge still does the forking
> thing.  The sound also changes from a thud to a throaty popping kind of
> sound.  I had this coil throwing out 34" sparks, and now I'm nearly a foot
> off of that.
>
>
>
>
>> John
>>
>>
>>
>> -----Original Message-----
>> From: Phillip Slawinski <pslawinski@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Mon, 20 Oct 2008 5:43 pm
>> Subject: [TCML] Odd VTTC Streamer Behavior
>>
>>
>>
>> Lately my VTTC has had some odd streamer behavior.  Streamer length
>> increases linearly when I turn the voltage on the variac up, until it
>> reaches about 90V and then the streamer forks into two shorter
>>
> streamers.
>
>> This occurs when I have a low pulse rate in stacatto mode.  Has this
>> happened to anyone else?  Does anyone know what might cause this?
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