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 #59110
Joined: Mon Apr 11 2016, 04:35PM
Location: Camarillo, California
Posts: 74
If I get a few spare IGBJT's I may try messing withe the smaller step-up transformer and try and see what caused the death of the devices. I'd monitor the CE voltage on the devices at a low voltage and see what is going on. I have a nice diff probe that will allow this.
Back to the original (500VA) transformer, I've been turning it on at full input voltage (130VAC) for weeks now and have had no problems. Sometimes the coil doesn't start up but I'd assumed it was because I randomly turned it on at a zero voltage point.
Registered Member #146
Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055
A level shifter (like what VTTC and microwave ovens use) might be a good option for a ramped SSTC as you still get a sinusoidal output that is simply offset. You need a large capacitance to hold up a SSTC's energy consumption, so an electrolytic type would be most convenient. It must be large enough that it does not get over-discharged, which can result in reversal of the charge polarity on the cap! You could add a diode to protect the capacitor from accidental voltage reversal, but if it suffers from this issue, then the capacitor is significantly too small and should be bigger.
For a coil that draws 20A peak off a ~300V peak line, i find a 2200uF shifter cap to be suitable, and up to 3300uF being about the point of no extra benefit. The diode sees significant peak current, so it should be oversized for 80A peaks. The capacitor needs to have a voltage rating of at least the peak line input voltage (so 200V probably). You should be able to scale these values based on the current demand of your coil. I've attached an LTspice simulation of the simplified circuit which includes line parasitics and protection diode and assumes the tesla coil looks like a constant current sink (at least its roughly true). ]ramped_sstc_level_shifter.zip[/file]
Registered Member #59110
Joined: Mon Apr 11 2016, 04:35PM
Location: Camarillo, California
Posts: 74
Steve,
Thanks for the information. I'll look into learning about the concept.
The .zip file opens up an .asc file which I can read using TextEdit on a Mac. But the file means nothing to me. Is there a program that runs an .asc file?
On a side note, thanks so much for all the information that you have posted about tesla coils. So far I have found it very useful and accurate. I did a version of your Mini SSTC that is working fine. (after I sorted out various grounding issues and blew up at least three Mosfet's).
Registered Member #11591
Joined: Wed Mar 20 2013, 08:20PM
Location: UK
Posts: 556
alan sailer wrote ...
Steve,
Thanks for the information. I'll look into learning about the concept.
The .zip file opens up an .asc file which I can read using TextEdit on a Mac. But the file means nothing to me. Is there a program that runs an .asc file?
On a side note, thanks so much for all the information that you have posted about tesla coils. So far I have found it very useful and accurate. I did a version of your Mini SSTC that is working fine. (after I sorted out various grounding issues and blew up at least three Mosfet's).
Cheers.
Yep:
Steve Ward wrote ...
... ... I've attached an LTspice simulation of the simplified circuit which includes line parasitics and protection diode and assumes the tesla coil looks like a constant current sink (at least its roughly true). ...
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.
Step Up Transformer
