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 #1389
Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346
I'm working on Uzzors' SMPS and have hit a small roadblock in construction. While testing, I was using a 3 ohm resistor as a load, which should give a load within the limits of what the supply can handle. However, I was only able to get 130W (20V @ 6.6A) at maximum power setting. Fairly quickly the transformer insulation melted and blew my mains fuse (hopefully not my IRFP250s). I was using an old monitor flyback core with a 130mm^2 cross section. My windings were 20AWG (.8mm) PVC insulated wire for both my primary and secondary.
Well, now that I know that doesn't work, what exactly do I need to do to make sure that this core can provide the 750W that I want it to, or should I consider buying a new core? Also, all of my components are good for 1200W+, but it was suggested on the HV chat that a flyback core is only going to be good for 6-700W. If I wanted to get a new core to up the power, what would I be looking for, and where (in the USA).
Registered Member #95
Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308
The resistance of the wires, even if only 0.5 ohms can drop a decent amount of voltage. Now the DC resistance might seem low, but remember that the skin effect kicks in too, increasing the effective AC resistance. At 45kHz, for 16A capable wire I would use four strands of 22AWG twisted together as litz wire. The primary only has to handle about 4-5A at full load so bifilar 22AWG should be enough. What limits power in transformers is how much power they can dissipate. A core can lose power through losses tied to drive frequency and/or magnetic flux being too high, but that's about it unless I'm mistaken. The other losses are copper losses from the windings, and ideally you want to fill the entire window area with copper to reduce the resistance as much as possible. So if you can the required number of turns in at the required thickness in the winding area, the core is large enough.
EDIT: I guess this should be copied onto my site as well.
Registered Member #1389
Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346
Hmmm, thanks Uzzors. I've got some 20 and 26AWG that I can wind into multifilar wire. I'm probably going to end up needing to get some magnet wire or a bigger core eventually.
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
Firefox wrote ...
Hmmm, thanks Uzzors. I've got some 20 and 26AWG that I can wind into multifilar wire. I'm probably going to end up needing to get some magnet wire or a bigger core eventually.
Regarding our chat the other night, I looked more into which cores there are to get at retailers, and the best buck for the money are some > 1kW ferrite kits from RS components, they are around 30 euro for the N27 material kit, 840mm^2 crosssection and 45 euro for a N87 material.
I haven't really found anything good at ebay, ham sites, other auction sites etc, just have to find large smps and salvage big ferrites :/
Registered Member #1389
Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346
Ugh. This just isn't going to happen with this tiny core. With a core cross section of 125mm^2 and a winding window of 500mm^2, I just can't fit all the copper and insulation I need onto the transformer... time to go looking for a new one, I guess.
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
I managed to get 60 windings of 2x AWG24 on for the primary and the 2x 25 windings for the secondary, each of the 25 consists also of 2x AWG24, its also way too small to handle what the 460s FET can put out :)
But it will be fine for testing while I figure some washers for that big core.
Registered Member #1389
Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346
Yep. Good luck, MadsKaizer. My testing is done, so I just need to find that core. Mayhaps I'll find a similar flyback core. If so, I'm just going to put the square sections back to back and make it an EE core to hopefully get the power I need.
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.
Ferrite Transformer Design
