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 #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
Well gabriel, your power level looks pretty close to mine, your capacitor is somewhat smaller, and you're likely using a smaller workpiece. Try putting some coins in, they have high flux catching area and should heat up very quickly, and you should be able to melt quite large pieces of aluminum too. If you kept the heating time too long without water cooling I'd even worry whether your caps got damaged by the conducted heat, you could at least use two buckets and soem tube if you don't have a water tap nearby.
I would try stripping your caps down to 2uF and try a 60V run, then add some back if the voltage doesn't sag too much.
Registered Member #2310
Joined: Wed Aug 19 2009, 08:04PM
Location: Santa Catarina - Brazil
Posts: 169
Well Marko! I got that idea of the coin too... It really heats very nice and almost started melting... I think that the secret is on the inductive coupling that the coil have with the material and it's shape... Maybe I'll need some bigger (And separate) heatsinks for my mosfets, some equally rated caps, and a rewound MOT... I'm a little scared to try a 72 run (or 60v when it sags) I don't know if the driver will "Like" that initial peak of 72v (I'm afraid to kill my mosfets) What do you think? Coz I think that if I get things to work with 60v, so maybe i don't need the MOT...(pretty diffcult to find here)
Thank you, and lets keep the progress of the topic and the project!
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
Hi gabriel,
the idea is to turn your supply on on mains side so that the circuit never even sees the 70V peak of fully charged caps. But I think it would be fine even if you plugged it straight in any way, I've overvolted mine a few times and it seemed quite resillent.
Registered Member #2310
Joined: Wed Aug 19 2009, 08:04PM
Location: Santa Catarina - Brazil
Posts: 169
So let me see if i understood, you're talking me to maintain everything wired out, and just turn on the both transformers using a switch on the 220v wall side? If is that... I've always done like that... Because my switch here is pluging and unpluging the transformers from the 220v mains... Isn't a good idea changinh the 470 Ohm resistors and maybe the 10K too, with higher values like 1K? (Using 60v)? And what about the ideia of the step up transformer? Is it easy to blow the driver up with it? I heard some folks saying that Inductance value of the two inductors may vary, (increase for more voltage (output), decrease for more current (output)). Is that true? Is that's true Ill try to take some windings of the inductors out.
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
I'm not sure why would you want astep up transformer with high supply voltage. I think it only makes sense if you're using like 12V and a lot of current.
I woulld leave the 470 ohm resistors, if they and the zeners are suitably rated, as they are.
Again, if the inductors re big enough that ripple current in them is minimal (as it should be for the operation of this circuit) then increasing them will have no effect at all. Too small inductors might lead to atypical operation with blown mosfets as the most likely result :(
Registered Member #2310
Joined: Wed Aug 19 2009, 08:04PM
Location: Santa Catarina - Brazil
Posts: 169
Oh, OK!...I understand... So the two Inductors are not critical componentes of the circuit... So... Turning the transformers on by pluging and unpluging them directly from the wall, the circuit will never "see" the 72v Peak?
I'll make some changes to Heatsinks of my Mosfets today, and see If I can get a MOT... I'll post news soon, as well as photos.
Thank you!
Got New Photos...
And a Video
What Do you guys think? Lets keep the progress of the topic! Post more videos of yours Marko!
Registered Member #3567
Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260
Hi!
I just bought 4 0.004 uf, 1.5 kilovolt, transmitting mica caps at 40 amps at 1 kilocylcle. Could I parellel them to get 160 amps at 1kilocylcle? Would they work?
Registered Member #1223
Joined: Thu Jan 10 2008, 04:32PM
Location:
Posts: 133
Looking very good! But, can we push this simple circuit even further? As we know, using low voltage/high current is making quite a lot switching losses. Can we resolve the problem using maybe 100Volts, even 200Volts but lower current for IGBT/mosfets? Ok, first of all we need separated bias supply for gates.
But the main problem is that quite low impedance tank circuit. There would be huge circulating tank current if we simply put 200VDC to that circuit!
Somekind of impedance matching network is required. Transformer? Yes, maybe.. but tank circuit has to be after the transformer (tho, it works on primary side but this method will make some big power losses in transformer and requires heavy duty transformer anyway).
Then what happens to the feedback? Im not so sure if it can be taken from the secondary (center tapped and grounded?) side of matching transformer...
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.
Royer induction heater
