Re: Some more Marx questions (fwd)

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Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 2 Jul 2006 11:04:24 -0500
From: Dr. Resonance <resonance@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Some more Marx questions (fwd)


The circuit I supplied works fine --- we use it on some of our Marx 
generators.  Just be sure to use a PLC or other timing device to 
automatically disconnect the power supply from the Marx circuit just prior 
to firing --- if connected the back pulse could damage the diodes.  We do 
this on all of our Marx generators using a cheap $150 PLC to control charge, 
disconnect, and firing relays.  Using a PLC to control the primary contactor 
and separate HV contactor allows for 1 sec buzzer warning, then 20 sec 
charging, then 1/2 sec disconnect, then 1 sec buzzer, one more sec delay, 
then firing.

The HV charge relay uses a 1 inch stroke solenoid attached to a phenolic 
strip to multiply (lever action) the stroke by 3 (3 inch spacing) to 
disconnect the power supply 1/2 sec before the Marx fires.  This is for 30 
kV charging --- longer stroke necessary for higher stage charge voltages.

Dr. Resonance


>
> I'm slowly working on my Marx. The 6 kV diodes arrived, so I made some 
> 42kV
> strings with 7 diodes per string. I put them into some nice little tubes I
> had, and the used brass tubing at the ends for the contacts. Fits nicely
> into a standard fuse holder.
>
> Anyway, to the questions: The diagram from Dr. R and others for the 
> voltage
> doubler with a center tapped transformer has the ground seperate from the
> negative side of the doubler. All the Marx schematics I see show the arc
> going to ground. In my case, I would want the arc to go to the negative 
> side
> of the supply for maximum spark, right?
>
> It seems however, that arrangment would be hard on the power supply. So, 
> can
> anyone point me to a schematic that uses a center tapped transformer with 
> a
> doubler to feed a Marx bank?
>
> Many, many thanks for all the help!
>
> Jonathan
> www.madlabs.info
>
>
>
>
>