[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: what happens if i use a marx cap arrangement on a TC?

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

> A Marx bank is a high voltage, pulsed DC device. A bank of High voltage,
> pulse duty caps are charged while hard wired in paralell. When the voltage
> reaches a set level (controlled by the spacing of several spark gaps, with
> the bottom one often a triggered gap) the caps discharge in series. If you
> have a bank of 10 caps in a Marx array and each cap is 100,000 volts, you
> only need a 100,000 volt DC power supply to charge them. But when they
> discharge, in series, you get 1,000,000 volts.
> Then you start over, this takes a LOT of time compared to the TC world
> chargeing takes 1/120th of a second.

You CAN run a Marx at 120 Hz... With fast quenching gaps (say, in H2), you
can run at 1000 pps. It's all in the charging circuit design (which is non
trivial for high rep rate marxes...)

The whole thing is, though, that TCs work just fine at the 10-20 kV level.
The output from a TC is really determined by the energy stored in the
primary cap. For a given amount of energy, it's going to be the same number,
size, weight, cost of caps regardless of voltage. In fact, as the voltage
goes up, it gets less "efficient" (in a $,mass,volume/joule sense).  Higher
voltages make sense if you need REALLY fast rise times (nanoseconds, or
sub-microseconds, at least) where you want low C.  TC's aren't a fast rise
time kind of device.

That said, there is something to be said for doing something different than
everybody else does.  Once you've got your vanilla TC running, try that