Re: [TCML] Brighten My Arc on my Tesla Coil

[Harvey Norris <harvich@xxxxxxxxx>]

--- On Thu, 4/18/13, Jim <electrical@xxxxxxxxxxxx> wrote:

> From: Jim <electrical@xxxxxxxxxxxx>
> Subject: [TCML] Brighten My Arc on my Tesla Coil
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Date: Thursday, April 18, 2013, 6:21 AM
> Hello Everyone,
> 
> Can you please suggest to me a way to increase the
> brightness of my arc on my Tesla Coil? It is a classic coil
> that uses 2 - 9,000 volt neon sign transformers. It stands
> about 48" high and produces up to 30" arcs. It uses a copper
> pipe type static spark gap. Here is a youtube video of the
> coil. http://www.youtube.com/watch?v=ewP4leT_C1I
> 
> Thanks,
> 
> Jim
On your primary schematic once the arc gap fires, it gives a low impedance pathway,(resistance of arc in series with primary) to the HV supply, essentially bypassing the much higher impedance cap in parallel used to resonate. If you switch the positions of the cap and arc gap in the schematic, L and C will appear together in series when the arc gap fires but now the arc gap appears as a short to the power supply. However what causes the arc gap to fire is when the charged cap can overcome the resistance of the open arc gap, and the charging cap being 90 degrees out of phase with the source voltage, will have reached its highest voltage at the point where the alternating voltage is preparing to reverse polarity; in other words at its zero crossing point. Perhaps this is the importance of having a properly quenched arc gap so that it ceases before the voltage builds up again on the reverse side of the cycle, otherwise that arc acting as a short would cause
 all the current to take that short path. Perhaps this is why some coilers claim they can run their system without transformer ballasting?(If the transformer is not current limited) An unballasted system run by a variac might reach a point of increasing the voltage input where these events are not bypassed in time once the voltage input reaches a certain level. Of subsidiary interest concerning ballasting see
Helium Bulb Resonant Current Ballasting via 48/1 step up transformer.
http://youtu.be/CjWTZIOK084
Input 12.7 V @ 2.08A  Transformer primary sees 2.75A  4:13 into video.
Ballasting method shows resonant rise of amperage
This method means if the load becomes disconnected the input A goes sky high as shown at end of video where 10A variac shutoff occurs.
Binary Resonant Tank Circuit as shown in video.
http://www.flickr.com/photos/harvich/6558719847/
Resonant Current Ballasting of a 1KVA 4/1 Step Up Transformer
http://youtu.be/f85IUR0XEcw
Enables > tripling of unloaded output voltage



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