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 #573
Joined: Fri Mar 09 2007, 11:26AM
Location: Russia
Posts: 14
Hi everyone!
I want to write a program for calculating pulse transformers like ignition coil, those used in stun guns etc.. But unfortunately i can find no theory for them, exept common description like this one:
Registered Member #146
Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055
This seems like a tricky one.
I believe you can model them similarly to a tesla coil, except the primary is "untuned". The basic operation is storage of energy in the primary inductance of the transformer. Then by interrupting the primary current, energy is forced out of the secondary winding. By conservation of energy you know what the output energy is, and if you know the L and C paramters of the winding, you can figure out what the peak voltage and current will be. For better predictions you can factor in winding resistance and possibly losses in the magnetic core material, but i dont know too much specifically about that. You also have to be sure you arent saturating your core, otherwise the calculations go right out the window.
The biggest problem will be determining the capacitance of the secondary winding. This factor is as important as any, so without knowing it, you wont have much idea as to the output voltage/current (though you can still know the potential energy there). I dont know of way to calculate this capacitance, it seems to be something that you measure experimentally (by knowing the inductance - which is easy to measure - and applying a step or pulse to the coil, you can find the resonant frequency and work out the capacitance).
Registered Member #227
Joined: Mon Feb 20 2006, 10:47PM
Location: Cambridge Ontario, Canada!!
Posts: 127
if You are just looking for testing, You could use a micrometer to adjust a spark gap, then You could estimate the output voltage, as for current, maybe a current clamp?
Registered Member #573
Joined: Fri Mar 09 2007, 11:26AM
Location: Russia
Posts: 14
I did a huge search before posting here. And all i found relates to left or say, low voltage side. This is well described on coilgun sites like this:
For example, i have modelled a typical stun gun circuit (1kv; 0.33uF; 0.1 Ohm; 15uH) This results into pulse width of about 8us and peak current of 140 A.
So, for the secondary winding we have pulse width, inductance, resistance (dc) and propably capacitance too. And we need to find optimum ratio between them. That's what i am asking about. Because *sorry* i was unable to find any information!
Maybe you will experience more luck, or you can just tell?
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
It's all just standard transformer theory. Or Tesla coil theory: a Tesla coil is just a pulse transformer with an air core, and a pulse transformer is just a Tesla coil with a ferromagnetic core.
The equations you would use are the same differential equations that a circuit simulator like SPICE uses.
You may not be able to rearrange these equations to get an analytic solution for the parameter you want to optimize. SPICE doesn't even try: it solves them by numerical integration.
My own interest was in finding analytic solutions to optimize solid-state Tesla coils, but I never got anywhere. I found one interesting transfer function that wasn't generally known, but I failed to explain it to anyone else. Terry Fritz made much better progress with a program that numerically solves the Tesla coil circuit over and over again, walking the solution space to find the optimum. I think: I never quite understood what he did.
I personally gave up on my analytic stuff and used parametric runs in PSpice to optimize my Tesla coil designs.
Registered Member #75
Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711
I think the main problem with ignition coils and the like is that in general you will at best have a vague idea about the capacitance and inductance of the secondary side given just geometric parameters. It's a lot easier to get accurate estimates of your circuit parameters with a nicely wound Tesla coil.
If you can measure these parameters, the maths is relatively straightforward. Look at weakly coupled oscillators, a concept that frequently comes up in physics, to see how the energy sloshes back and forth between primary and secondary side.
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.