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Re: Tesla/Marx generators.
Hi Daniel,
You pose a good question IMO:
> RE;
> another thing that made this Tesla coil somewhat unconventional was the
> fact that the resonating capacitor was connected directly in parallel with
> the primary of the Tesla coil. The Marx multiplier would dump a nice big
> bunch of energy into the L/C primary circuit, and then the primary would
> happily ring away until it was hit again by the next dump of energy. Note
>
> But how could the Marx generator, or any other HV source charge the
> resonating cap if it's directly connected to the primary? The DC resistance
> of the primary, only a fraction of an ohm, would surely prevent, (or short
> out,) any potential applied. It's my understanding that the purpose of the
> gap is to electrically separate the primary from the cap so that charging
> can take place to a certain value. When the gap fires, it's the equivalent
> of a switch closing and that's when the show begins.
>
> Facinating phenomenom! Comments?
>
> Daniel Hess
The secret is in the high impedance of the primary coil at *very*
high frequencies. According to a piece in Sargent and Dollinger's
book "High Power Electronics", spark propagation is on the order of
10^-8 s in a typical spark gap (compare that with the sine period at
the resonant frequency of the coil). I have built Marx banks that
actually use this trick. By replacing the normally used resistors
with chokes, you can speed up recharge times, eliminate power loss
that normally occurs with the resistors and still get much the same
output.
A bit off-topic,
Malcolm