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Re: HV DC power supply design

Tero,

The list wisdom from past posts (see the archives) is that if your series
connected diodes are all the same type, and the diode PIV rating is at least
twice what they actually encounter, then don't bother with equalizing
resistors and capacitors.  Just string diodes in series.  So if you use
1N4007s, just make sure the PIV across each diode is not more than about 500
volts, and they should do fine without Cs and Rs across them.

I have made a pair of half wave voltage doublers for two MOTs, giving plus
and minus 4.5 KV respectivelly, for a total of about 11 KV output.  The
diodes are those used in microwave ovens, and should be OK without putting
them in series.  (Actually, the factory makes them using a bunch of diodes
in series, packaged into one unit.)  They are typically rated at 15 KV at a
few hundred ma.   I use oven caps as well, with the output caps for each
doubler being two sets of two series caps in parallel (4 caps) to stay near
one microfared, but at twice the voltage.  I do have resistors across these
caps, both to equalize voltage and to discharge them for safety purposes
when the supply is off.

Be careful messing with your DC supply - it can kill you if you are
careless!

--Steve Young



----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, January 08, 2000 12:34 PM
Subject: HV DC power supply design


> Original Poster: "Tero Ranta" <tero.ranta-at-bigfoot-dot-com>
>
> Dear List,
>
> as you might have noticed, I'm trying to design a stiff DC power supply
> using two MOTs and a voltage doubler pair. It's not only for TC use. I'm
> looking for general HV DC power supply design guidelines, how to do the
> diode/capacitor strings, how to calculate needed values for filter caps,
how
> to connect the voltage/ampere meters etc.
>
> I have a 1996 ARRL (radio amateur) handbook, which has a tiny section on
HV
> power supplies, it tells me what I should do in general, like use many
> diodes in series, but that's not enough, because I'd like to know what
> cap/resistor values should I connect in parallel with them etc.
>
> I have a tendency to screw up things, that's why I want to even once do
> something that ends up working well for years. :-)
>
> If you know a good source of information regarding the subject, please let
> me know.
>
> Thanks in advance,
> Tero.
>
>
>