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 #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
Here it is. I've completed all the components and have begun assembly. Any feedback is greatly appreciated at this stage. I really just want to be sure I'm on the right track. All pics are below including the schematic I'm following. I'm assuming the safest bet is to ground the NST to RF, not house. Also, before you warn me I am going to install a strike rail. The NST is 15kv 60ma The A/C filter circuit consists of an RFI EMI Tesla Filter 15 Amp's 115/250vac and 2 PFC caps from microwaves in parallel totaling 165uF. TeslaMap suggests 165uF for optimum PFC. Capacitor measures 10.9nF - resonant cap for this NST is 10.6 (at the time I didn't know an LTR was better or I would have added more plates). It's constructed with 30 sheets of 8 X 10 polyethylene windows and 28 sheets of aluminum foil. It will soon be replaced with an LTR MMC. I've already ordered 40 0.15uF, 2kV 942C20P15K-F caps and will be assembling 2 strings of 17 for a total of just over 17nF. Toroid is 4" aluminum ducting with aluminum tape wrapped all around it and 8.5" pie pans bolted in the center. When I entered it's dimensions in TeslaMap it said the capacitance is 18.3pF
Registered Member #2989
Joined: Sun Jul 11 2010, 12:01AM
Location: UK
Posts: 94
A few things I would look out for Keep all the HV parts smooth, so there's less likely to be any unwanted break out you may want to put some plastic between coils, it might flash over near the bottom part make sure the tunings ok take your time over this bit put a sharp breakout point on the top so you know were it should be sparking from If there's any small fires turn it off quick :)
Registered Member #6038
Joined: Mon Aug 06 2012, 11:31AM
Location: Salado, TX
Posts: 248
This build looks good. Nice construction too. I love the NST protection features - you will be happy you have those in place. I learned the hard way With regards to the ground, I always grounded the secondary to a dedicated RF ground, but kept he NST grounded to the house ground. I would worry about ground loops, but I am no expert. One of the best spark gaps I ever built was a forced air quenched gap. It worked really well. Fast quenching really helps. That said, I wonder if the length of copper tubing will allow the primary spark to travel along its length for too long before being extinguished? How do you adjust the spark gap for max voltage?
Registered Member #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
Graham Armitage wrote ...
This build looks good. Nice construction too. I love the NST protection features - you will be happy you have those in place. I learned the hard way With regards to the ground, I always grounded the secondary to a dedicated RF ground, but kept he NST grounded to the house ground. I would worry about ground loops, but I am no expert. One of the best spark gaps I ever built was a forced air quenched gap. It worked really well. Fast quenching really helps. That said, I wonder if the length of copper tubing will allow the primary spark to travel along its length for too long before being extinguished? How do you adjust the spark gap for max voltage?
Each copper pipe is 4 1/4" long. I got the design from youtube and the guy showed it in action in a later video, seemed to work great. The gap between each one is 1/32", I got that from a couple different coilers. As far as adjusting the gap, I can change it but it would take a good amount of time so I'm just hoping it will work the way it is. Some day I'm going to design one that can be adjusted by turning a screw. As far as the NST grounding I had the same concern, you're probably right. I'll just change it to mains ground. Thank you, and thanks for the compliment.
Registered Member #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
Blackcurrant wrote ...
A few things I would look out for Keep all the HV parts smooth, so there's less likely to be any unwanted break out you may want to put some plastic between coils, it might flash over near the bottom part make sure the tunings ok take your time over this bit put a sharp breakout point on the top so you know were it should be sparking from If there's any small fires turn it off quick :)
Thanks. You mean plastic between the bottom of the secondary and primary right?
Registered Member #2989
Joined: Sun Jul 11 2010, 12:01AM
Location: UK
Posts: 94
yes, like a plastic tube to stop it jumping from the inner primary coil to the secondary. It might not happen but it does look close to me. If your gap fails to fire, try a re-tune or link out one of the gaps.
Have you thought of a safe way to discharge the caps? If something fails there could still be charge in them, trust nothing! Also the secondary coil may hold a bit of static after use
I am a bit worried about the terry filter -did you remove the unnecessary copper pads from the board ? On some of those boards the distance between them is really small (for easier soldering) and might flash over.
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Some of the Vero-board is completely copperless, and this one looks to be that.
I'm a bit concerned about your 630V caps, I think they're going to die. You might want to try to run your filter with some high voltage for a short while, turn off, and see if the caps are hot.
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.
At the assembly stage. Looking for feedback (no pun intended)
With regards to the ground, I always grounded the secondary to a dedicated RF ground, but kept he NST grounded to the house ground. I would worry about ground loops, but I am no expert. One of the best spark gaps I ever built was a forced air quenched gap. It worked really well. Fast quenching really helps. That said, I wonder if the length of copper tubing will allow the primary spark to travel along its length for too long before being extinguished? How do you adjust the spark gap for max voltage?
