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 #58215
Joined: Wed Dec 30 2015, 11:27AM
Location: Boise, Idaho
Posts: 65
A senior at my school is building a can-crusher for a project, and needs a capacitor on the magnitude of 60uF and 10kV. He is having trouble finding capacitors that fit. Does anyone have any suggestions as to how to acquire this much capacitance/voltage for the cheapest price? Good advice would be websites that sell, other places to find caps that big or smaller caps that can be added together to get fit the requirements.
He has found one for 1000$ that fits, but is hoping to find something cheaper. Any help is appreciated.
Registered Member #58215
Joined: Wed Dec 30 2015, 11:27AM
Location: Boise, Idaho
Posts: 65
He's looking up that cap size, when he googled it a can crusher popped up at that exact size/voltage and impressed him. Should save him some money, thanks Signification
Registered Member #54278
Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367
Yeah, I just googled the same thing and saw the caps and a video of a can crusher. The guy running the crusher does NOT know how to handle high voltage!! He uses no eye/hearing protection, and puts both hands on a high energy components--looks like he assumes no voltage remains after the cap fires! A good way to die--fast!...notice that immediately after the can is crushed, he grabs the can--one hand on top and the other on bottom--INSANE! This is a great video on how NOT to handle high voltage/energy circuits.
I have heard that something like 40 Joules or less can be lethal -SOMEONE PLEASE CORRECT ME ON THIS IF IT'S DIFFERENT---A 5000V @ 100uF capacitor can store 1,250 Joules (over 30x the lethal level)!
I understand this is a high school student--Please make sure you get proper experience and instruction before doing this! These pulse capacitors actually --go-affter-you--may sound crazy, but be scared of them!! I have always believed that charged high voltage/energy caps are the most dangerous components. BTW: three defibrillator capacitors in parallel can be close to what you want. You need pulse rated caps.
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
Less than 40J can be lethal too, it depends on many things, how you get shocked, voltage, current, total charge etc.
With a single shock from a capacitor you are most likely to risk heart fibrillation. A normal defibrillator used by paramedics (or the modern use by everyone and their dog) uses from a few Joules up to 360, so it surely won't kill you by guarantee.
Shocking yourself with a high voltage capacitor is however not going to end well, the energy is delivered too fast, a defibrillator has a large inductor to slow the current pulse down.
Play it safe, use NC grounding circuits at power loss, atleast 2 different charge indicators so one can fail. Only operate it through isolated mechanisms like strings, rods, air, fiber optic.
Registered Member #58215
Joined: Wed Dec 30 2015, 11:27AM
Location: Boise, Idaho
Posts: 65
Signification wrote ...
Yeah, I just googled the same thing and saw the caps and a video of a can crusher. The guy running the crusher does NOT know how to handle high voltage!! He uses no eye/hearing protection, and puts both hands on a high energy components--looks like he assumes no voltage remains after the cap fires! A good way to die--fast!...notice that immediately after the can is crushed, he grabs the can--one hand on top and the other on bottom--INSANE! This is a great video on how NOT to handle high voltage/energy circuits.
I have heard that something like 40 Joules or less can be lethal -SOMEONE PLEASE CORRECT ME ON THIS IF IT'S DIFFERENT---A 5000V @ 100uF capacitor can store 1,250 Joules (over 30x the lethal level)!
I understand this is a high school student--Please make sure you get proper experience and instruction before doing this! These pulse capacitors actually --go-affter-you--may sound crazy, but be scared of them!! I have always believed that charged high voltage/energy caps are the most dangerous components. BTW: three defibrillator capacitors in parallel can be close to what you want. You need pulse rated caps.
There are a lot of vids like that. It gets worse, as some people trigger their circuits by grabbing an exposed wire with a glove and jamming it against another wire, making a huge spark. It's somewhere around .002 A that is lethal- it will cause arrhythmia, then a range above that is "safer" until you get to the point where the current can start cooking you.
Senior in College, actually, not high school. We have as much instruction as we'd ever formally get, so it's more about not being stupid.
Play it safe, use NC grounding circuits at power loss, atleast 2 different charge indicators so one can fail. Only operate it through isolated mechanisms like strings, rods, air, fiber optic.
We'll probably trigger with a spark gap, so isolating ourselves any time the caps are charging up won't be difficult. I don't know what backup "safe discharge" he has planned but I'll make sure there is one.
Depending on the price of the caps he'll want 2 100uF 5kV to make a 10kV cap, or maybe higher with more of them. I'll post any other questions we have here if they arise. This should probably be moved to high voltage?
Registered Member #54278
Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367
You know that would then knock your capacitance down to 50uF, which may be OK. You would need FOUR 100uF @ 5kV capacitors to get 100uF @ 10kV (2s2p). If over 1kJ is involved, I try to avoid "series".
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
I'm with Signification and Kizmo in the club of people totally crushing cans, or tearing them in half, with 1 kJ or less. But capacitor voltage rating should be at least a few kV. Trying to do it with less voltage, e.g. electrolytics, will be even more horribly inefficient. For a given energy, the optimum number of coil turns goes up with V. But it can't be less than 1!
Used defibrillator capacitors are all over the place and will become more common. Definitely up to the task of can crushing, but it's hard on the capacitors unless you use more than one. Lots of posts about it 10 years ago by Peter "tesladownunder" Terren.
Mads Barnkob wrote ...
Less than 40J can be lethal too, it depends on many things, how you get shocked, voltage, current, total charge etc. With a single shock from a capacitor you are most likely to risk heart fibrillation. A normal defibrillator used by paramedics (or the modern use by everyone and their dog) uses from a few Joules up to 360, so it surely won't kill you by guarantee.
A paramedic, on his fourth day on the job, playfully zapped his co-worker as they rode in an ambulance. She died. I think modern automatic defibs will not fire unless they detect a bad heart signal. That smartness is not built into the capacitors!
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.
[moved] Where to get high voltage capacitors (10kV+)
I have always believed that charged high voltage/energy caps are the most dangerous components. BTW: three defibrillator capacitors in parallel can be close to what you want. You need pulse rated caps.
