On Sat, Jun 23, 2018 at 9:22 AM charles rakes <crakes29@xxxxxxxxx> wrote:
> I built the Marx generator about 3 or 4 years ago before the price of the
> 30Kv capacitors got to today's higher price. Started out with two towers
> of 10 stages each and that worked so well that I added 5 more stages to
> each tower. In the beginning I did have some problems with my charging
> system which I overcome with added protection circuitry. It fires about
> once every 5 seconds with the power supply set at its maximum voltage.
> Also built a small dual tower unit with small disc caps that produces about
> a 1ft spark. Just wish there was a source of less expensive HV caps and
> I'd try for a larger set of towers. Charles
>
> On Sat, Jun 23, 2018 at 6:38 AM, David Rieben <drieben@xxxxxxx> wrote:
>
>> Charles,
>>
>> Wow! 36” spark! That’s impressive. I happen to have a surplus x-ray
>> transformer (with its internal diodes still intact) that I currently
>> already have set up to be fed with the current ballasted 0 - 280 VAC output
>> from my large Tesla coil control panel that would serve admirably for
>> feeding a ‘man-sized’ Marx generator. I have toyed with the idea of
>> building a big Marx bank before, but the challenge of its sound
>> construction, both from an electrical as well as a mechanical standpoint,
>> the unlikely prospect of procuring all of the required matching HV Caps and
>> resistors on the surplus market and the consequential cost associated with
>> obtaining the same on a retail market, and the total lack of space to
>> safely operate such a beast have pretty well placed that project on the
>> back burner for now. :-/
>>
>> David
>>
>> Sent from my iPhone
>>
>> > On Jun 22, 2018, at 8:26 PM, charles rakes <crakes29@xxxxxxxxx> wrote:
>> >
>> > I use a 15Kv 60ma NST with 30 diodes in series on each output hot
>> > terminal. One string with a negative output and the other with a
>> > positive. I get over 22KV DC output that I use to drive my dual 15
>> stage
>> > Marx generator and get about 36-inches spark between the two towers.
>> The
>> > NST's primary is controlled by a variac.
>> >
>> > On Fri, Jun 22, 2018 at 2:14 PM, Matthew Sweeney <msweeney23@xxxxxxxxx>
>> > wrote:
>> >
>> >> Hi Raymond, I did this using strings of cheap Microwave oven diodes
>> potted
>> >> in short PVC tubs with paraffin wax. I also added some high wattage 1M
>> >> resistors for my own safety.
>> >>
>> >> Basically I created large, clunky, cheap 30KV-50KV diodes :)
>> >>
>> >> It worked well, but I think the diodes would be better off in epoxy
>> >> specific for the context. Rectified DC off an NST is a different beast
>> and
>> >> kinda scary for me :)
>> >>
>> >> I was using this to drive a VDG, but the voltage was too high and it's
>> very
>> >> much overkill!
>> >>
>> >> Good luck!
>> >>
>> >> On Fri, Jun 22, 2018, 5:35 AM Raymond Spigot <
>> raymond.j.spigot@xxxxxxxxx>
>> >> wrote:
>> >>
>> >>> Hi, thanks for all the interesting discussion about NST testing and
>> safe
>> >>> grounding, it's all been instructive for a noob
>> >>>
>> >>> I have this grey resin block neon transformer in the shed I was
>> thinking
>> >> of
>> >>> experimenting with. It's a 15kv/30mA one with a midpoint ground
>> >>> connection. Is there a way to rectify the output so I can use it for
>> >>> trying out powering a dc tesla?
>> >>>
>> >>> I have a big bag of diodes (1N5408 I think) that were pretty cheap.
>> If
>> >>> they'll handle 1000v each I could solder them up into long strings and
>> >> use
>> >>> 4 strings of diodes to make a bridge rectifier? I guess I'd need a
>> >>> capacitor on the other side of the bridge as well though to smooth it
>> >> out a
>> >>> bit.
>> >>>
>> >>> Then I was wondering if there was another way to do it with a midpoint
>> >>> grounded transformer like mine. I'm thinking the 2 secondary
>> windings on
>> >>> the transformer must be out-of-phase, but could I rectify them
>> >>> individually? Between each HV output and the midpoint ground I mean.
>> >> Then
>> >>> I'm thinking I'd need 2 bridges but they're only trying to rectify
>> half
>> >> the
>> >>> voltage each and it would be easier to cope with.
>> >>>
>> >>> Basically I'm hoping there's a way to get like 10kv dc out instead of
>> >>> closer to (I think) 20kv Because then I can buy a main MMC capacitor
>> >> that
>> >>> doesn't have to be rated for the highest voltage (so I can put less
>> caps
>> >> in
>> >>> series)
>> >>>
>> >>> hope this makes some sense to someone! thanx for advice anyway
>> >>>
>> >>> Ray
>> >>> _______________________________________________
>> >>> Tesla mailing list
>> >>> Tesla@xxxxxxxxxxxxxxxxxx
>> >>> https://www.pupman.com/mailman/listinfo/tesla
>> >>>
>> >> _______________________________________________
>> >> Tesla mailing list
>> >> Tesla@xxxxxxxxxxxxxxxxxx
>> >> https://www.pupman.com/mailman/listinfo/tesla
>> >>
>> > _______________________________________________
>> > Tesla mailing list
>> > Tesla@xxxxxxxxxxxxxxxxxx
>> > https://www.pupman.com/mailman/listinfo/tesla
>>
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxxxxxx
https://www.pupman.com/mailman/listinfo/tesla