AC Marx

Electroholic, Fri Sept 29 2006, 12:29AM

Ok, I know Marx are DC,
but if I have a marx that is designed to run at very high pulse rate(much higher than 50Hz),
I should be able to run it with HVAC, right?
Like a basic tesla coil?
Re: AC Marx
Steve Ward, Sun Oct 01 2006, 10:51PM

Well, the main issue is charging the capacitors in that 10mS time frame. Inductive charging would probably work. I've done work with inductively charged marx generators, and they work great provided L is very large. Just how large depends on a few factors, mainly the Fo of the LC combination and the rise time of the output... think of a stepped cosine function, if the output doesnt reach max very quickly, the voltage starts to oscillate down to zero (as the cosine function crosses zero). With resistive charging, the output is present, and decays as an RC (negative exponential) function, which is usually far "slower" than the LC oscillations.

I couldnt get past about 20 shots a second with my marx because the spark gaps would stop quenching. Normally the resistors will choke this out, but the inductors just dont present much steady state impedance (only the DCR, which is small). If you could solve the spark gap issue, then it should be very possible to have a marx fire at 100hz or more... i havent had time to figure that out yet. It should be noted that the stress on the capacitors will be much larger, since there will now be a very significant RMS current through them (due to the high rep rate of the discharge), which could cause heating/failure.