Re: Why is the coil being weird???? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 08 Nov 2007 18:26:51 -0800
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Why is the coil being weird???? (fwd)

Hi Jay,

Sounds like a static gap that is heating up quickly. Keep the gap cool 
when running to prevent this. Two things that really help is 1) a fan 
(no big surprise) and 2) a pipe gap with about 1" tube diameter which 
allows a large surface area for thermal dissipation (inner and outer 
walls) and is thin enough to allow a fan to stabilize the temperature.

The voltage required to arc the gap decreases with temperature. 
Therefore, the cap is charged to a lower value when the spark gap 
conducts. So, with less energy in the cap at the time of conduction, a 
weaker magnetic field is produced at the primary and results in a low 
energy transfer to the secondary. So, sparks get shorter. All this can 
happen pretty quick.

Take care,
Bart

Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Wed, 07 Nov 2007 21:49:41 +0000
> From: jhowson4@xxxxxxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: Why is the coil being weird????
>
> I have been tinkering with my coil for a while now and it has been acting weird since the day I built it.  but it is just starting to get on my nerves.
>
> So basically
> When I run my coil at first if is good.  producing 30" sparks lots of noise etc.  
> But after about 5-6 seconds it just craps out.  The spark gap stops making the normal loud spark gap sounds and it starts to make a really quick softer sound.   Like the one the tv makes when there is no channel and just static.  At the same time the sparks length drops to about 4".   
> I turn it off.  let it chill for like 30 seconds and then it does the same thing.   If I turn it off and don't let it chill it just does it quicker. 
> Very annoying.  
> I am currently using 5 obits in parallel and 2    .005uf home made capacitors.  The spark gap is 2 bolts less than 1/4" apart in a tube that is connected to the blowing end of a vacuum.  The frequency is about 600kHz.  
> Any ideas and  help will be great.
>
> Many thanks,
> Jay Howson
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