Re: HV DC power supply design

To: tesla-at-pupman-dot-com
Subject: Re: HV DC power supply design
From: DickHamly-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 10 Jan 2000 12:32:52 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

I built a ten stage Cockroft Walton (series of voltage doublers) generator 
similar to yours but using a 15KV NST as the input.   It made a big fat spark 
a foot long.   Within a short time I blew a lot of expensive diodes.   
Instead of buying new diodes and trying to optimize the  protective shunts 
and caps, I just built a ten stage Marx generator (charges caps in parallel 
and discharges in series via spark gaps), using the same caps and the same 
NST.  

Because it has only caps, resistors and spark gaps, it is much more robust 
and much more forgiving to the experimentor.   It will produce a spark 
similar to the Cockroft Wallton but it takes more time to build up the 
charge.   That is due to my choice of resistors.   I will eventually reduce 
the values of the series resistors to allow faster charging.   It is unerving 
to operate.   It hisses and buzzes and crackles with corona as it charges up. 
  Then, suddenly, BANG, like a shot gun, the big, fat, foot long spark!    It 
scares the crap out of me every time but it works.   
I am building a Spark chamber for which it will be the power supply.

After you guys work out a reliable design for the Cockroft Walton and after I 
find an infinite supply of diodes, I might try it again.

Good luck.

Dick Hamly