Need info on Varian/Wallis CW multiplier

[MRMILSTAR]

I saw this Varian/Wallis CW multiplier on E-Bay. The model number is H1260001. I am considering buying it but I can't find any information about it. I believe the maximum voltage output is 180 KV even though the description says 300 KV. It appears to be a 8-stage unit, possibly full-wave design. The capacitors are rated for 30 KV so am guessing that the required power supply would be around 10 KV RMS for good design margin. There also appear to be internal resistors on each stage. I would probably use a big flyback transformer and a ZVS to power it. I think that I would have to supply some external load resistance to avoid damage since I want to produce sparks to ground. Here is a link. Any info would be much appreciated.

https://www.ebay.com/itm/Varian-Extrion-Cockroft-Walton-Multiplier-High-Voltage-Power-Supply-300kV/154112197476?hash=item23e1cd8364:g:uuUAAOSwU~BfdSLx

[plasma]

It looks like 10-11 stages, should be all right to short to ground. You will need high frequency and high current source. The caps look like 10nF / 2 series * 10 stages 50nF charging current per cycle, about 500mA.
Just released that if its the design I think, every cap stages sees multiple of input voltage, you can only run it at 3kV

[davekni]

I'd agree that 300kV isn't realistic.  Not sure how the seller came up with 10 stages.  Looks like it might be 9.

The caps are likely 1nF (based on their "1n0 K" label) film caps.  Also agree that some form of output ballast is needed, as the caps aren't likely rated for extreme dV/dt.

Depending on the effect you are after, you could make an air-insulated capacitor to follow the ballast as I did for my Marx generator:


The long black tube is a 12mH inductor (ballast) wound around 3" PVC pipe.  Of course, parameters would be quite different for DC charging.  In my case, charge transfer takes 3us, just slow enough to keep the Marx generator pulse-rated caps within specification.  Output arcs are very loud with sudden discharge from the low-inductance output capacitor.