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 #3075
Joined: Fri Aug 06 2010, 02:44PM
Location: Athens, GA
Posts: 148
My water lines are PVC...
I was thinking of going with the 9kV in order to keep the size of the TC small (2" X 10" secondary), and my output somewhat smaller (max of around 12-15" streamers to ground, maybe 5 or 6" to air). Want to run this in the kitchen on the table. Also, wouldn't the 9kV also require a smaller MMC?
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
A nice piece of rebar pounded into the ground also works if you're pipes aren't grounded.
It will be very tough to get sparks of that size with a 10" coil. Expect sparks like this from a well made one. It looks like 15" tall by 3" wide.
edit, below is useless info as you did a ninja post.
Go outside and look at the place where you're power comes in and look for a wire going to a pipe. (sometimes this may be near the gas meter too)
A good way to test if your water system is to make a crude crystal radio. Just up the "positive wire" of a germanium diode to a piezoelectric ear bud. Touch the "negative side" to a water pipe, and pinch the other wire of the earbud in your fingers. If your pipes are properly grounded, you should hear a random am radio station.
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
If you're looking for a small portable Tesla coil, try using a 4kV/20mA or 6kv/20mA or 6kV/30mA NST. Franceformer makes at least the 6kV/30mA NST in an open frame version which is pretty inexpensive.
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
9kV/30mA will work - just depends on what you consider a mini coil. If the coil is only 12" high with a small toroid, then the 9kV/30mA is probably overkill.
I have my specs on a mini Tesla coil utilizing a 4kV/38mA transformer. They can be found on the following page:
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
Grenadier wrote A nice piece of rebar pounded into the ground also works if you're pipes aren't grounded
If your project is powered by the mains, the rebar must be bonded (connected) with same size wire that mains system uses to its ground point. Otherwise it causes more trouble for reasons covered in numerous other posts.
Registered Member #3075
Joined: Fri Aug 06 2010, 02:44PM
Location: Athens, GA
Posts: 148
Thanks for the replies guys...
Daniel, thanks for the link...I have been over your site before, and there's great info there! In fact, I used your 'how I design my TC's" pdf extensively in learning about how to plan the components (though I got it from another site of yours I believe?). I do plan on using the 9kV Franceformer I have...may just have to up-scale my coil a bit to 3" secondary if 2" is too small for that size NST. I notice in your docs you advocate using a resonant cap bank (relative to the NST). Do you still agree with this, or is the 1.7 LTR better for the life of the NST?
Edit - found the pdf I have at home...it was labeled from when your company was Space Cat...damn fine document!
Registered Member #2416
Joined: Sun Oct 04 2009, 04:23AM
Location: Oceanside, CA
Posts: 91
Arcstarter wrote ...
Grenadier wrote ...
Yes. And don't follow deepfried neon's calculator. It tells you to design a resonant cap bank, and those often fry NST's. You want to build a cap that is larger than resonant for you're primary.
Well, you want the cap to resonate with the primary. You just do not want the capacitor to resonate with the NST's secondary, because of resonant rise causing over voltage, and over current. The deepfriedneon calculator will show you the resonant cap, which you want about 1.7 times that size for LTR.
Yup, technically the LTR size is the resonant cap multiplied by the golden ratio (1.61803399). That's because you'll avoid any higher harmonics with that size. That number is interesting because if you square it you'll get that same number plus one, I though it was kinda interesting.
I've used a resonant cap size without issue before but LTR is a safer way to go.
HM_Murdock wrote ...
Does going LTR remove the need for protection between the cap and the NST, or simply augment it?
I am thinking that if I go LTR and use a safety gap, the NST secondary will be safe? Again, please correct my assumptions if wrong...
If you really want to protect your NST you'll wanna build a Terry Filter safety gap.
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.
power supply...NST vs. FBT
