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 #3862
Joined: Wed May 04 2011, 03:04AM
Location:
Posts: 5
Hi, I'm building a coil similar to the SSTC5 and was just curious to how the UCC37322/1 pair work... I just want to clarify it in my head. Also for a 3.5"x20" secondary with around 850 turns that has a resonant freq of around 308kHz, how many primary windings should I have?
Registered Member #1875
Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635
The UCC gate drivers are just high speed buffers that can source high peak currents for driving capacitive loads. One is inverting. There is a pin that forces a LO output state, as well. What they do together as a pair is turn a DC square wave into an AC one (as in, there is a negative voltage swing), which is needed for driving transformers of a gate driving nature...
Registered Member #3885
Joined: Sun May 15 2011, 12:47AM
Location: Newton, Massachusetts, United States
Posts: 94
As for the primary windings, there is no "correct" or "resonant" value if you're running an SSTC (as opposed to a DRSSTC). From Richie's site:
"The choice of Lp and k are very important. In fact I think that one of the main challenges in solid state Tesla coil work is in juggling these two parameters to get maximum power transfer into the resonator.
If Lp is too small, the magnetising current becomes unacceptably high. Although this does not contribute to the supply current of the driver, it does contribute to heating in the switches. It also increases the current ripple seen by the supply reservoir capacitors.
If Lp is too great, then there is little step-up due to transformer action. As a result, the Tesla resonator is not well matched to the driver, and little power is drawn from the driver.
If k is too small, then the load current is dominated by the magnetising current, and little of the current supplied by the driver actually contributes to resonance in the secondary winding.
If k is too great, then there is a risk of electrical flashover. This is due to the close proximity demanded to achieve this degree of pri-sec coupling, and the large sparks that result !"
Registered Member #3862
Joined: Wed May 04 2011, 03:04AM
Location:
Posts: 5
Cool...thanks for that...also what do the capacitors in the mosfet bridge do? In SSTC5 there are two 0.68uF ones, and in the full bridge in SSTC2 there is one from supply to ground and one in series with the primary.
Registered Member #1875
Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635
You need snubber capacitors across each leg of your bridge to suppress spikes at turn-off. They need to be physically close to your switches. These are the ones from supply to ground. They need to be some sort of film capacitors. I have lost many devices due to insufficient snubbing. A capacitor in series with the primary is not terribly necessary in an air core transformer but can be helpful in certain situations. If you are using a GDT to drive the gates then those situations are not likely.
You can also add more capacitance from supply to ground for a cw coil. These should be large size, high current rated (computer or inverter rated) electrolytic capacitors.
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.
SSTC Questions
