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 #4603
Joined: Wed Apr 25 2012, 07:33PM
Location: Austria
Posts: 159
Thanks!
Yes, of course.
I tuned the coil to the upper pole. Just moved the primary tab a bit lower to get a higher primary frequency and that forced the coil to oscillate to the upper pole. The frequency went up to >400kHz. The UD always showed the OCD LED running on such high frequencies. That was the main problem... I did not realize that the UVLO was the problem until i scoped the 24V of the UD board. The voltage dropped significantly. I added 6000µF to the 24V rail and set the UVLO to about 20V - then it worked Now i am going to build a casing for the coil so that i can run it outside with more power/longer ramptime and higher voltage on the bridge.
Hey fantastic job there and it looks like you’re getting about the same performance as my QCW was. I’m glad to see the QCW driver is working well!
As you have found, upper pole tuning works better for QCWs where the added streamer pulls the coil more in tune, as opposed to lower pole operation, though ideally I would run the coil with the primary tuned lower but driving at the upper pole. This is a bit difficult with the direct feedback UD driver without some modifications.
The wires and heatsink / heating are usually not a problem though especially in the low-duty cycle cases likeT what RateReducer and my coils are doing. This becomes much more relevant in high duty cycle operation, though of course some proper litz wire is always good. And as you found out, it wasn't the OCD kicking in but the UVLO due to the large drive required. The modifications I made to the UD2.7C were inspired exactly because of the UVLO and gate drive power required I was seeing in QCW use, though I wind my GDTs for +-20V operation just to reduce the total gate drive power required. I presume you are using the full 24V gate drive on your 8-bridge?
Looking forward to more sparks when you move the coil down to the floor! The composite photo of the sparks hitting the walls is very cool. Good luck!
Registered Member #4603
Joined: Wed Apr 25 2012, 07:33PM
Location: Austria
Posts: 159
Hi loneoceans!
Yes, there is huge difference between upper and lower pole tuning. Tuned to the upper pole the streamers are much longer but not as thick like on the lower pole tuning. I use 24V, yes. With the added electrolytic caps and UVLO adjusted to 20V it works. A casing for the coil is in the works The casing will consist of 4 levels. The cap(s) for the buck will be 30.000µF @ 400V - that should do ^^
Registered Member #4603
Joined: Wed Apr 25 2012, 07:33PM
Location: Austria
Posts: 159
Made some progress on the casing.
I am worried about the distance primary - bridge and GDT. Is the distance shown on the 2nd pic to close? Now i am still able to move the last plate, the threaded rods are not cut yet. I just want to keep the casing as small as possible...
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.