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 #30656
Joined: Tue Jul 30 2013, 02:40AM
Location: UK
Posts: 208
To help clear up the discussion about Steve Ward vs EVR methods, this is what is on their respective web pages:
From (EVR site): "One (1) of the 0.1uF, 2kV capacitors is used as a primary strike transient suppressor and protects the half-bridge power electronics from secondary voltage strikes which may hit the primary coil. This capacitor is tied directly between the output of the half-bridge circuit and chassis ground via the heatsink."
Their diagram:
From (Steve's site): "Notice that if the coil arcs to the primary system, either the IGBTs or diodes (which are always there) will let the current go safely back into the DC bus caps, where it can couple through C3 (a 100nF PP film cap) to the ground connection of the secondary coil. If the capacitor was not there, then it would likely blast through to the heatsink and destroy the IGBTs insulation. Or, it will find some other way. The idea here is simply to provide an excellent path for the streamer current to take, simple. "
Steve's diagram:
They look different to me, though maybe EVR suggests the same method as Steve elsewhere. It looks like mbd found the same info on EVR's site as above, and had the same thoughts as I did about the capacitor loading the bridge.
Registered Member #43278
Joined: Sat Feb 22 2014, 09:18AM
Location: Sydney
Posts: 9
Hydron's reply identifies exactly the issue I was trying to raise.
Normally, I would ponder a response like:
To clarify, I mean it's exactly the same...
for quite a while before I posted a follow-up, but in this case I think that I will really struggle to work out the reason behind Eric's statement unless someone offers me a clue ... (My apologies if the reason is obvious to more enlightened beings.)
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
It is not "exactly the same"- in the EVR method the high frequency output of the bridge is injected onto the heatsink through the first capacitor, where it then gets shorted to ground, for extra stress, carnage and malfunction.
The methods are only equivalent in so far as the DC bus bypassing should look like a short circuit at high frequencies, so it shouldn't matter whether you bypass one pole of the DC bus to the heatsink, or both.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
I don't get this as well. A relatively large cap from bridge output to ground would just cause a horrible RF interference as well as extra stress on the transistors, which could even be fatal. And now realize that these coils are being sold even for professional purposes, for no little money.
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
Good information everyone. I agree with your assessments of this bypassing scheme and that it definately warrants additional attention and re-examination.
Thanks for bringing it out and discussing it. This is what makes 4HV so great!
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.
Primary strike protection for DRSSTCs
