Re: HV going to DC (fwd)

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Original poster: Tesla List Moderator <mod1-at-poodle.pupman-dot-com>



---------- Forwarded message ----------
Date: Fri, 23 Mar 2001 12:20:39 -0800
From: Jim Lux <jimlux-at-earthlink-dot-net>
To: Tesla list <tesla-at-pupman-dot-com>
Subject: Re: HV going to DC

To turn HV AC into HV DC there are several ways.

First, you need to rectify the AC.  
Easy way: Use a HV diode, either vacuum tube or semiconductor.  Vacuum HV diodes are tough, but expensive, and you have to have a filament supply, etc.  Semi's are a bit more fragile, but much cheaper, don't get hot, etc.  Two basic kinds:
 ones made as HV rectifier (i.e. microwave oven rectifiers.. about $10-20 new as a replacement part for a 10 kV, 200 mA part) about the same from K2AW (who sells 14 kV, 1A parts)
the other, ones you make yourself by stringing a lot of lower voltage diodes in series.  A run of the mill 1 kV diode like a 1N540x series, or the more exotic parts rated at 3-6 kV (but still cheap..).  Figure on a 50% margin.. i.e. if you need a 10 kV rectifier, you'd better string together 15 of the 1kV parts.

Harder way: More exotic rectifers.. 
Corona forms more easily for one polarity than the other, so you can make a rectifier with a point working against a plane electrode.
Synchronous rotary rectifiers - spin a rotary switch at line synchronized rate. The CO2 laser in the Amateur Scientist used this technique...

Then, you might need to turn pulsating DC (rectified AC) into smooth DC.  For this, you need a filter of some sort, for which there are two basic alternatives: series inductors and parallel capacitors, or combinations of the two.


Tesla list wrote:
> 
> Original poster: "jkooi by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jkooi-at-wish-dot-net>
> 
> greetinx every 1,
> 
> How can i get DC out of my HV AC  power supply
> 
> regards, J Kooiman