Re: diode protection

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Allanh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <allanh-at-starband-dot-net>

Skip Home Depot, they're too expensive, go to your local electrical supply
house and you can get the very same , or in most cases better, electrical
box for about $8.

allan

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, August 30, 2002 10:58 AM
Subject: Re: diode protection


>
> Original poster: "Daniel Barrett by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <dbarrett1-at-austin.rr-dot-com>
>
>     Hi!
>     My setup is similar and in about the same stage as yours. I'm not sure
> what type of diodes you are using, but let me share a few things that may
> help. My exuberance and outpouring of funds has been running unclamped on
> this PSU for a couple of weeks now ;)
>
>     1) Go ahead, break down and put the reactor under oil. It's messy, and
> doesn't sound like fun but It's worth the trouble. Home depot has these
> great waterproof electrical junction boxes with no holes in them. My
reactor
> fit in a 8x8x4 inch model, about $20. If your reactor flashes over you
have
> just toasted a lot of magnet wire, diodes and time. So invest the time-
You
> will get good results.
>
>     2) Use fast-recovery rectifiers for the de-queing diodes. 1N4007's
will
> not survive if used much above 60Hz. I have burned up about 400 of them
> learning this. I'm having good luck with Gen Semi UF4007's from Mouser.
> These are $.19 each, I use a string of 20. This is a 100v, 1amp, 75nS
unit.
>
>     3) you can use a series resitor, but it's not necessary if your
> inductors are not flashing over and your caps are not exploding. It just
> burns power and acts as an expensive slow-acting fuse. The silicon fries
> faster than the resistor...
>
>     I'm running a single MOT feeding a quadrupler feeding a 9H reactor for
> 20kV at 90mA. Streamers are about 4.5 feet at 1100VA input power as of
last
> night, power supply is running cool and no fryodes. No protection or
> filtering of any kind. Just a lot of mineral oil all over the place ;)
>     Hope this helps!
> db
>
>
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Thursday, August 29, 2002 7:14 PM
> Subject: diode protection
>
>
> > Original poster: "Wells Campbell by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <wellscampbell-at-onebox-dot-com>
> >
> > hi list,
> >
> > I am working on a small MOT DC maggie, and am currently in the "advanced
> > cobble up"stage. Mine is of the type recently discussed, a doubler /
> > reactor setup, which I have been able to run at low power a few times.
> > As with many on our list, progress has been mainly dependent on the slow
> > trickle of funds I have allowed myself to put into the project. I am
> > at the point now where the most recent run produced 1 foot streamers
> > into open air, and I was able to sucessfully control power by varying
> > the break rate on my ASRG, which pleased me greatly. The sound was cool
> > too, somewhat like a whiny siren that changed up and down as I dialed
> > my variac.
> >
> > Then my cap (party plates in oil in a bucket, very crude) popped. Time
> > to get out the salt and foil and drink some beer!
> >
> > then my MOT reactors started to flash over (naturally, they aren't in
> > oil or anything) and my PS started to eat diodes which (naturally)
aren't
> > protected or anything.
> >
> > Anyway, I'm satisfied enough with results so far to start putting
together
> > the final version, and I had a few questions.
> >
> > Does anyone have any advice on a diode protection filter arrangement?
> > I like Greg Hunter's arrangement, I thought I would use those 10kv /
> > .001 uFd ceramic caps at all electronics, one in parallel with each (MO)
> > diode. Is this too much capacitance?
> >
> > Then I was thinking of using a pair of power resistors after the
de-Q-ing
> > diodes and before the reactors (one per HV leg) to attenuate spikes from
> > the reactors, as well as those from any flashovers that may occur in
> > the future. What would be a good value? 1k ohms? 100 ohms? Also should
> > I use chokes too for an LCR  network, or should I not bother because
> > the reactors serve this purpose? what about a safety gap? where would
> > it go? seems like anywhere i put it it would power-arc.
> > Any advice would be helpful before I pour tens and tens of dollars into
> > components :>)
> >
> > My shematic is similar to the one on Greg's site, "speculative DC
reactor
> > setup". I will post pics and details soon, but feel I should make a
little
> > more progress first. My power switch is still an old power strip and
> > a bamboo chopstick (i'm not gonna touch that thing!) :>)
> >
> > Also, a filter that instantaneously clamps outflow of funds as
exuberance
> > begins positive cycle would be helpful.
> >
> > Cheers,
> >
> > --
> > Wells Campbell
> > wellscampbell-at-onebox-dot-com
> >
> >
> >
> >
> >
>
>
>
>