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.
Capacitors sort of scare me. Even flash caps. I still feel uncomfortable using them and typically handle them with much more care than I did yesterday around my NST. But how is that a sillyscope probe? Hm I need a new one, mine is broken.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
HighVoltageChick wrote ...
Capacitors sort of scare me. Even flash caps. I still feel uncomfortable using them and typically handle them with much more care than I did yesterday around my NST. But how is that a sillyscope probe? Hm I need a new one, mine is broken.
You can get the standard 10X probes on ebay, 2 probes for $15-40. My design here is for a specialized application.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
New progress.
These next few pics show the construction of what i call the "High Voltage RC Element", this device is a SSX39 MG resistor, 125 Mohms in parallel with a coaxial 4.9-5.2 pF oil capacitor, both are meant to withstand 14 kV. 3 of these "elements" will be in series to obtain a 42 kV probe of 375 Mohms, at 1.5 to 1.7 pF. I just pray the field distrubution and capacitence is enough, the Northstars have 10 pF for a similar spec'ed probe. The bottom most plate is insulated from the resistor body, as the voltage drop beneath it is 800 volts less then the plate. This probe will be oil filled and have a 10,000:1 division ratio.
Sheet metal and copper ring.
Plates of steel and copper soldered and epoxied, then attatched as per the FEMM model for field distrubution.
Temporary hot glue mock up to test fit and funtion, this will be redone in oil proof epoxy soon.
Seen here in my hand.
The resistor's V drop is linearized with the cap plates, and grading rings.
Registered Member #1321
Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843
Patrick are those resistors made by EBG?
If so the data sheet says this: "Our resistors are designed for operation in air and not agressive [sic] atmospheres. For special applications (i.e. oil, casting, moulding, SF6, etc.) please contact your nearest EBG representative."
I don't know why there should be any issues with oil or an encapsulant, but have you asked them about that?
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
jpsmith123 wrote ...
Patrick are those resistors made by EBG?
If so the data sheet says this: "Our resistors are designed for operation in air and not agressive [sic] atmospheres. For special applications (i.e. oil, casting, moulding, SF6, etc.) please contact your nearest EBG representative."
I don't know why there should be any issues with oil or an encapsulant, but have you asked them about that?
Yes already cleared that up, oil is fine. Ive had contact will Del/Spellman HV corp and EBG they all say oil is fine, ive figuered out a way to leave the silicone coating on and still find the lower drop end, so that resistor will be the last one you see with the white and black stripes.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
jpsmith123 wrote ...
According to Wikipedia: Sic is a Latin word that means "thus" or, in writing, "it was thus in the source material".
Basically I just used it to indicate that the misspelled word appearing in the quoted text was that way in the original text and not my mistake.
The usual usage is described here:
Didnt know that...
jpsmith123 wrote ...
BTW I think I will use some of those same resistors in my voltage multiplier. I guess it's ok to encapsulate them in silicone rubber?
yes silicone is fine, the only hazard with ridgid epoxy is that a gap can form between the resistor body and encapsulant which then becomes atmosphere filled and causes corona problems. You can avoid this problem by using dimensionally/thermally stable epoxy or just soft silicone. (Or if your a real man you can use oil)
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.
High voltage probe for O-scope, 1 of 2, ( DEVELOPMENT ).
