Re: diode protection

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

Original poster: "Daniel Barrett by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dbarrett1-at-austin.rr-dot-com>

    Hey Wells!
    More comments interspersed...


> >     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

>
> Wow, sounds like quite a performer. That must be a chunky MOT you've
> got. is it one of those Advance Transformer co. rated 4000 volts?
>
> Also, if you wouldn't mind, could you tell me about your reactor? Do
> you use another MOT, or did you wind your own? This is another area where
> my coil needs work. Unfortunately, I don't have an L meter, so this may
> have to be done by estimation and trial, so info on yours would help.

    Yet another plug for the $120 Wavetek 27XT. It's a big help.


> I've toyed with the idea of using an MOT core wound with 22ga magnet
> wire (heavily shielded, of course) or even a winding on a pvc pipe with
> a core that could be pulled in and out to add adjustability. All just
> ideas now, my cobble up used three MOT's in series and seemed to work
> ok.

    I took an old MOT and ripped all the windings off. Fortunately the
laminations were set up so that all the "E"'s were on one side. I chisled
the core in half and busted off the 'I" laminations, so I was left with two
E laminations, half the width of the original MOT. Then I hacksawed out the
middle leg of the core (the one which originally held the windings). This
left me with 2 'C's. As I read this it's starting to sound like gibberish so
maybe I should just send you a picture :)
Next I made a couple of spools out of  1 1/4" PVC pipe about 4.5 inchs long.
Each spool is divided into 4 sections with 1/8 acrylic separators- so they
are really wound as 4 inductors (inductorettes? subductors?). Each got wound
with #24 until the wire was about 3/4 inch thick. Each took about 3 pounds
of wire. When I stuck them on the core I was pleased to discover the pair in
series gave me 24H,  more than enough. I then played around with gapping the
cores until I got 9H- turned out a piece of 1/8 acrylic did the job nicely.
You could get by with less wire than I used- I just wanted to be sure I had
enough leaway to play with. I'm getting tired of winding progressively
larger reactors and wanted to be "done" :) This thing can be adjusted from 3
to 24H by the gap  distance in between the core halves.
    The power supply is nothing special- The MOT cranks out about 2300 VAC
feeding a positive and negative half wave doubler. This charges a filter cap
of 4- 1UF microwave caps. Unloaded output is about +/- 6kv. This then goes
through the fast-recovery diode strings to the reactor. Let me know if you
want me to send you pics of the setup- I don't have a website up yet, but I
can send some pics and schematics to anyone interested-
db


db