Re: marx chokes

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Greg Leyh <lod@xxxxxxxxxxx>

The inductance of a Marx choke is not the critical parameter, but rather 
the volt-seconds it can support without saturating.  Design the Marx choke 
simply as a pulse transformer, without a secondary.  The primary and core 
must be able to support the Marx cell voltage over the duration of the 
pulse.  Here's a pic of a Marx choke [labeled isolator in the pic] that's 
actually wound 4-in-hand to pass DC power up the stack as well:
http://www-group.slac.stanford.edu/esd/NLCMarxCell.gif

This Marx cell is part of a larger Marx bank, outlined here:
http://www-group.slac.stanford.edu/esd/NLCMarxBlock.gif

The Marx choke is tapewound copper foil over Kapton onto a stock MetGlas 
core, and can support 1.5kV for about 2 uS.  Come to think of it, I didn't 
actually measure it's open ckt inductance, but would guess it's a good 
fraction of 1H.

-GL



> Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>
>
>
>
> Malcolm:
>
> What was the value of your chokes?  I would like  to try this idea as well.
> Digi-Key stocks a large number of iron core chokes.
>
> Dr. Resonance
>
>
> >
> >
> > Use chokes instead of resistors. The benefits: much faster and more
> > efficient charging (far less resistive loss). As to the values,
> > mileage varies. There is balance between charge time and sufficiently
> > high impedance at discharge time. I built two working Marx banks,
> > both of which used chokes wound on ferrite rods. I spoeculated at the
> > time that suitably sizing the components might allow resonant
> > charging at mains or some other nominated frequency but pursuing the
> > idea is way down my list of things to do.
> >
> > Malcolm
> >
> >
> >