ZVS driver diode failure. / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

ZVS driver diode failure.

previous 1 2 3 next

Move Thread

LAN_403

Matt Edwards

Wed Aug 11 2010, 02:19AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

Here is the parts list from mouser that i purchased. I obtained the list from another 4HV thread

. Worked pretty well. Obviously you can use various other components but these have proven to be vary reliable for me. I was pumping 48v through mine before the flyback died. It was producing somewhere around 6" arcs maybe more... If you choose to supply a higher voltage though, i would suggest a higher current resistor rather than the 2w ones. And possibly a higher rated zener. The resistors seem to get hot pretty quickly at 36V+ and I have blown up a few zeners.

Don't beat yourself up too much. Everyone makes simple mistakes from time to time. When I first applied my driver to a board I could not figure out why it would not work. I eventually realized that I had placed the two zener diodes backwards...

1. Mosfet's------ IRFP250PBF-------------- 2
2. Zener Diodes------ 1N5349BG--------------- 2
3. FRED Diodes------ HFA15TB60PBF ---------- 2 (These are hard to find in-stock. NTE578 seem to work well also.)
4. 470 Ohm 2W Resistors------ 282-470-RC----------- 2
5. 10k 2W Resistors------ 282-10K-RC----------- 2
6. 0.68uf Pulse Film Capacitorr------ 75-MKP1841468254------------ 1
7. 47UH 10.7A Inductor------- 2309-V-RC----------- 1

teravolt

Wed Aug 11 2010, 04:47AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

recently I was powering a 16 stage trippler with my mazillii circuit and blew some components so when I rebuilt it I added a 220v transorb accross each collector-emiter junction and a 18v tranz in parallel with each zenar now I can draw 14" sparks no problem.
Just remember that the primary is a parallel tank circuit and when the primary resonance is the same as the secondary you get voltage so playing with with the primary capacitance can tune it. If it is out of tune it will behave like a transformer. Because the primary is a parallel circuit circulating current is high and impedance is high This is why a poly cap with low ESR is important and a hevey gauge primary helps. I
use 16 to 14 gauge with about 4-6 turns. When everything is working good the primary and secondary will be warm. when I got my first setup working good I was geting 2-3" out of a little 2" flyback on till it finaly shorted. Any how thats my 3 cents on the subject.

Pripyat

Wed Aug 11 2010, 02:12PM

Registered Member #3086 Joined: Sun Aug 08 2010, 08:35PM
Location:
Posts: 9

Thanks for the tech info, teravolt. I didn't even attempt to analyze this circuit, so your explanation was helpful. Unfortunately, the major limitation of my flyback is that there is very little room to wrap my new primary. I am using more like 18 or 20 gauge wire just so I can get 8 turns. Here is a photo that illustrates my space constraint:

The Flyback

14 gauge is out of the question unless I start cutting into the plastic.

teravolt

Wed Aug 11 2010, 07:36PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

if you can find on ebay or othter place a old style flyback from yeseryear they are not shrouded so bad. just add another set of primary windings like the first and parallel them. if you can find them look for this style

also information unlimmited has a set of surplus flybacks you can buy resonably

Matt Edwards

Thu Aug 12 2010, 12:20AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

TERAVOLT- Not to get off subject but 14" is pretty impressive. Would you care to share a photograph? Maybe you could draw up a quick schematic for all us newbies so that we can try out your mods?

PRIPVAT- That flyback that teravolt is suggesting is capable of producing some nice output. I have a few similar ones. It may be possible to produce as much as 40-60KV AC if it is similar to the one that i have. If you don't fry it, you could build a nice Marx or CW generator and get some really nice arcs. Just a thought...

If you get everything running smoothly you may want to try the revision by Andrinerii which includes an additional 3x3 turns for feedback on top of the 5x5 primary and two 100 ohm resistors. It is listed here near the bottom.

I was vary happy with the increase in performance compared to the 4x4 or 5x5 turn setup.

teravolt

Thu Aug 12 2010, 03:11AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

hello all, here is a link to the video for my 160kv full wave 16 stage cocroft walton voltage multipier and a picture of my latest mazzilli circuit. All of the flybacks have the same resonant frequency and 2 are in phase and 2 pairs out of phase.

this multiplier started out smaller and then grew and then I stoped because the carona is every where and desperatly needs feald shapers. what you see in the picture is the mazzilli power supply for a marx I am invesigating.

Pripyat

Tue Aug 17 2010, 12:39AM

Registered Member #3086 Joined: Sun Aug 08 2010, 08:35PM
Location:
Posts: 9

Wow, Teravolt.. That looks impressive...

I put my driver back together with the new capacitor. It works much better than the previous circuit did before it burnt up. I ran it for a minute or so at 2" and the mosfets were barely warm.

The small flyback with 4+4 22 gauge created a 2" fuzzy arc. I got a different flyback and wound 14 gauge wire on it. 4+4 turns. The arcs were ridiculous. I was getting over 3" lightning bolt style arcs for about 10 seconds. Then the transformer died.

Why are some arcs 'fuzzy' and others like lightning? How can I prevent from killing my transformer?

Matt Edwards

Tue Aug 17 2010, 12:52AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

Teravolt- how do you prevent arcover between the diodes? I once got arcover on one of those pretty red caps you are using. You have to be pushing well over 40-100k by that point right? I was getting about 50k when experiencing this.

Xplorer

Thu Aug 19 2010, 10:06AM

Registered Member #2416 Joined: Sun Oct 04 2009, 04:23AM
Location: Oceanside, CA
Posts: 91

Hey guys. I'm in the process of building this circuit too. I found a Lambda power supply that has some X2 MKK caps. One is 470nf and the other 220nf. How do you think they'll do in parallel, 690nf, it should be okay right?

Pic:

About the inductor, is 170uH required or is there some leeway on that? Also from that Lambda power supply I found a 2 cm diameter ferrite toroid. I double wound it with 22 turns of 22 gauge magnet wire. I'm going by this calculator, and assuming the core permeability is about 200.

22 turns should give me ~150uH.
If I'm interpreting this circuit correctly doesn't the inductor act as an inductive ballast for the primary, in which case it's value will effect the output?

Pic:

Oh BTY if anyone else needs parts, I got pretty much everything from Futurlec. They've got a great selection of all kinda of goodies.

Thanks

-Tony

teravolt

Thu Aug 19 2010, 07:13PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

nice work Pripyat if you want bigger sparks get your self some doorknob caps 40-50k and a lot of 1n4007's and make your self a HV dubbler. Remember its about 10kv per CM rouhgly.

Oidium45 to insulate my full wave dubbler. I went down to tap plastics and had them cut all the pieces for a custom size box and glued it my self. the dubbler is then mounted in the box then I poured melted perifin wax and made a big candle out of it. pictures later

hi there the first picture shows what it looks like before potting the second is molten perifin and third cooled

previous 1 2 3 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob