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Re: using XC to cancel XL



Hi James,

> Original Poster: "The Flavored Coffee Guy" <elgersmad-at-msn-dot-com>
>Here's how to avoid that problem in a small discription,  use a
>rated spark gap, or a spark plug that you can gap yourself, a
>diode, and a larger cap.  In the circuit arrangement the order
>of parts would be as follows: 120 AC, Diode, or bridge rectifier,
>Filter capacitor, Spark gap, NST.  You can even the control the
>frequency that the gap fires.  Filter capacitor, Inductive choke,
>tuning capacitor, spark gap, NST.  Which would be a pi filter,
>charging a small cap before the spark gap, feeding the NST
>the same way you would feed the primary of the tesla coil.
> There are spark gaps, and gaps small enough for 120 volts to
>jump.  It might take 15, er 20 non-resistor type plugs to do it
>but, they will work, if you know how to adjust the gap of a
>sparkplug..

I donīt think this will work, unless you use some kind of
resonance trick. Getting any kind of "straight air" gap to
self trigger under ~300 volts is next to impossible. Secondly,
even if you get the gap to fire, you will really stress the
rectifier as the cap discharges into the NST and recharges
there after. Of course you could design a remote triggered
"low" voltage gap by pre-ionizing the gap with a shot of HV,
but I think this is more trouble than it is worth.

Lastly, I am not sure if this really helps output. Itīs more like
a single shot (even if repetitive) circuit. Charging such a cap
to a higher voltage than the NST was designed for, will most
likely lead to increased stress (and heat) in the NST primary
as the core will start to saturate (which lets the primary
winding look more and more like a short than an impedance).

Raising the input frequency of an NST will also result in increased
losses as the iron canīt follow the increased "beating" properly. It
might be an idea for a ferrite powered HV supply unit, tho.

Coiler greets from Germany,
Reinhard