If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
While cleaning out various boxes in the lab, I came across some of my first high voltage projects, among them, a mazilli driver built on a veroboard, which resulted in quite a few blown traces due to the high currents :)
I decided to rebuild it in the same style as Myke do most of his small projects, but since I had to reuse the old components it did not turn out as good :)
I tried with 4 different flybacks, a standard TV flyback, portable tv flyback, photocopier flyback and a very old disc flyback with rectifier tube, the photocopier and rectifier tube did not surviwe.
Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
Looks very nice :D.
I cannot tell, but about how many turns is your inductor? It should be around 50-100 or something like that, probably much more. Another member suggested around 100-200 is correct (it was '...' iirc). He actually put an inductor in the migratory junk box he said had about half enough turns i think, and i took it and that is what i used in the ZVS. The first mosfets on my ZVS where from the junk box, the UF4007's where from there, and i used Ultra7's large green 100 watt 1kohm resistor, tapped in the middle for 2 500ohm 'ressitors'. It heats quite a bit despite the very large wattage rating. The energy you do not lose in heat on the mosfets is lost in the resistor XD. At least at 700 watts -.-
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
Arcstarter wrote ...
Looks very nice :D.
I cannot tell, but about how many turns is your inductor? It should be around 50-100 or something like that, probably much more. Another member suggested around 100-200 is correct (it was '...' iirc). He actually put an inductor in the migratory junk box he said had about half enough turns i think, and i took it and that is what i used in the ZVS. The first mosfets on my ZVS where from the junk box, the UF4007's where from there, and i used Ultra7's large green 100 watt 1kohm resistor, tapped in the middle for 2 500ohm 'ressitors'. It heats quite a bit despite the very large wattage rating. The energy you do not lose in heat on the mosfets is lost in the resistor XD. At least at 700 watts -.-
I got no heat losses in resistors or any other part than only a little on the mosfets.
the inductor is 12 windings of 12 or 14AWG, measured 170uH
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
It depends on the core, for the yellow/white powdered iron cores in an ATX psu you need 100-200 turns (50 would be pushing it depending on the core), but it looks like he is using a ferrite core in this project which needs only 10-20 turns.
It should be noted that the circuit will operate differently with the ferrite core than a powdered iron one, because the ferrite is going to saturate quite quickly--although it has been shown time and time again that this does not seem to hurt the output very much. If anything the only result is more heating in the fets (I generally see the fets mounted in gigantic heatsinks with using a ferrite core, when using a powdered iron core with enough turns I run 500w for hours using heatsinks about 1/10 the size of the one shown in the first post)
Looks great overall! I might suggest doing something to stabilize the output connector a little, it sucks to dig a project out of a box and realize that you snapped off one of the pins on your fets
Registered Member #540
Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969
It looks really nice. I like how you ran the wires that go to the flyback between the two heatsinks.
With my design, it can be kinda annoying to remove the MOSFETs because they are soldered in. I made the diode/resistor thing have little feet at the end of the leads so that it can just sit on top of the MOSFET's leads.
Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
All my components laid down, to give just enough clearance for the lid on the box i made for it. I used terminal blocks, which i would highly recommend. If you lived in USA i would ship you a few no charge -.-.
On the two drain wires, i cut some insulation off a few cm's down, and soldered the capacitor to it right there. This means short leads to the capacitor.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Very nice. The reasons I don't like this circuit much are the arc screaming before going out and the flyback core getting smoking hot. But it has its place, mainly because of its simplicity-to-power ratio Anyway, I should mention this
P.S. I have some experiments with my super simple self-oscillating bridge going on, so be prepared for another simple and powerful driver unfortunately I don't have much time now, but when I get to it, I'll surely post the results.
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
If your core gets hot it means your are saturating, and you need to use more turns on the core (or possibly add more of an airgap). The screaming can be solved by using a smaller tank capacitor.
The mazzilli driver does have its drawbacks, but the two you mention are pretty easily solvable.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
... wrote ...
If your core gets hot it means your are saturating, and you need to use more turns on the core (or possibly add more of an airgap). The screaming can be solved by using a smaller tank capacitor.
Well, this circuit from design needs huge amount of reactive power circulating between the tank cap and the core, I think someone (Sulaiman?) said the Q must be at least 5, so if you're outputting 500W, the core sees 2.5kVA (AT LEAST!)
Airgap seems to solve the screaming but makes the core even hotter, because it oscillates on a higher frequency so the hysteresis losses are higher.
Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
Dr. Kilovolt wrote ...
Very nice. The reasons I don't like this circuit much are the arc screaming before going out and the flyback core getting smoking hot. But it has its place, mainly because of its simplicity-to-power ratio Anyway, I should mention this
P.S. I have some experiments with my super simple self-oscillating bridge going on, so be prepared for another simple and powerful driver unfortunately I don't have much time now, but when I get to it, I'll surely post the results.
Hmm, to me it seems this thread might result in good info :P.
Well, with none of the 15 or so flybacks i have killed have i had screaming arcs, or core heating. I did with one absolutely amazing flyback, with about 50 volts idle and 45 volts under load. It pulled almost 25 amps, was about 1000watts and VERY high voltage. It was DC.
My homemade HV transformer never had this problem either, but the screaming and heating has to do with the characteristics of the core and primary inductance and cap, primarily. (Unless the secondary also plays a major role?)
By the way, i am looking forward to your driver! For like a year now i have considered you the king of flybacks. I did make a multipurpose inverter that i drove a flyback with, using a stupid 555, thanks to the idea i got from you on youtube .
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.