Remember me

[ ]
[ ]
Guests: 25, Members: 0 ...

most ever online: 333
(Members: 3, Guests: 330) on 06 Jun : 15:15

Members: 3396
Newest member: ghilinta.daniel
Members Birthdays:
All today's birthdays', congrats!
Gagazet (25)
Chris Cristini (28)

Next birthdays
07/22 Reaching (32)
07/22 ryanshow (30)
07/23 Will (30)
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!
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.
4hv.org :: Forums :: Tesla Coils
<< Previous thread | Next thread >>   

2017 DRSSTC completion and first light

Author Post
Sun Jul 09 2017, 02:19PM Print View
Registered Member #54930
Joined: Tue Apr 28 2015, 01:38PM
Location: pittsfield ohio
Posts: 23
Hi all, I just finished my big TC using 4 CM600HA-24 IGBT's. The h-bridge was a duplicate "thanks to pictures" from Phillip Slawinski on the web. I was able to visualize the design from the pictures and re-engineer it into the bridge I built. From there I was able to construct the rest of the hardware required for the entire build. I did run into some electronic stumbling blocks which stopped me cold. They involved the CT ratio's and the CT material. Also the GDT arrangement. But I contacted Steve and he provided me with the correct basics to construct and test them myself. Thanks again Steve!

I had met Steve long ago on two different occasions at the Teslathon in NY at Ed Wingates. The first time was prior to any SSTC or DRSSTC's....only rotary spark gap. The second meeting was when Steve and another young man had brought their SSTC's to Ed's and ran them. It was this time that was so compelling that I had to build one of them for myself. I remember the arcs were so bold, blue, and thick and I remember being scared to death because it was so much more powerful than Ed's extra coil.

I have no formal education in electronics at all. I started 2 years ago teaching myself by doing. My background is in tool and die and Eng. and in business. I think the biggest asset to this build was that I had built 6 tesla coils previously thru a 15 year period. One of them was the minibrute from scratch. This construction was a huge education in IGBT switching but only on a half bridge arrangement. Going to a full bridge was a little bit different but now that I have completed it I see there is not much difference. Did not know one could drive 4 IGBT's with one GDT! Also did not know how to setup the OCD.

I know some of you are going to question the red stripe on the secondary.....I ran out of gold wire and had red. The toroid was a copy from Finn Hammer's picture on the web. Once I saw it I just knew I had to build it. The strike rail is a new design that I am willing to bet no one else has. It is one continuous switchback that does not overlap. This idea came to me from a total failure I had built and welded. It was a beautiful hinged arrangement that wrapped around the primary for easy disassembly. It looked like a big fence. I sent Steve a picture and he immediately wrote me back stated that this will not work and why. So after all that work, time, and material I made a sketch and built it by undoing all the welds and rebuilding it into what is seen now. It is really cool. It is made from 1/8 ridged electrical conduit. I bent the tubing on my #2 Cincinnati vertical mill then tig welded the assy together. I then used some plexi to maintain the gap spacing.

Specs on the coil can be found here:

Video of the coil is found here:

Construction pictures found here:

I power this coil with a 90 amp 240vac variac. I am only feeding 240 to the coil which has an onboard voltage doubler which works fantastic. The coil only draws 40 amp. at 2400 amp on the primary. This has been verified by an additional CT "thanks again to Steve's suggestion". The primary is cooled by an aux cooler. The sec is wound on a sonotube and is lightweight and very easy to disassemble. The toroid is made from 1/8 alum plate with lightning holes and .040" alum tube. All tig welded and very light weight. I plan on taking it to Roger Smith's Teslathon in Chillicothe Ohio on August 19th.

I am fully retired now after 48 years and have plenty of time to pursue more projects like this. I consider myself fortunate to live close to CTR surplus and made off with several truckloads of stuff before they shut down. This kept the build price low. I am also fortunate to have a manufacturing background which makes construction a breeze. When I look back at where I started 15 years ago with this hobby I cannot believe how far my education has grown and how far I have come due to shear determination and hard work. I never stop wanting to learn and do. Too bad we cannot live for 800 years like Noah!

This project was way cool and so are the arcs!

Forrest "Bud" Mohrman
Back to top
Mads Barnkob
Sun Jul 16 2017, 05:10PM
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1909
Great looking coil with so many beautiful details that I can not even start to list them :)

I look forward to see more videos from Roger's Teslathon.

Could you please upload some of the pictures to 4hv, those with the specifications and design in? Which peak current setting have you this running at?

When I try to see the large pictures on photobucket it just says you have to upgrade the account to use it with 3rd party hosting. But eventually got it to work when going back to your profile and going into the album, not sure what went wrong there.
Back to top

Moderators: Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Bjørn, Dave Billington, Steve Conner, Wolfram, Kizmo, Mads Barnkob

Jump:     Back to top

Powered by e107 Forum System
Legal Information
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.