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 #1918
Joined: Fri Jan 09 2009, 07:22PM
Location:
Posts: 1
This is my first proper HV project other than messing with small flybacks. My final aim is to build a safe demonstration unit for use in high school physics demonstrations.
The can crusher is built from two 5kV 40uF capacitors in series charged to around 9kV. The power supply is an 8kV RMS NST with full-wave rectification through a diode bridge. I'm using a Fluke 40kV probe to measure the voltage across the capacitors and all the capacitor connections are made with flattened copper pipe. For testing purposes I'm attaching the diode bridge with croc clips which are removed before firing, since I have no protection against reverses. Again for testing purposes I'm firing the coil by simply using a long plastic pipe to push the end of the coil against a copper bar.
Testing
I initially wound a 6 turn coil of 16 awg copper around an 8.2cm plastic pipe (just large enough to fit a can inside), with disappointing results. The can was deformed, but not as much as I had hoped.
Then I decided to wind the coil directly on a can, again with 6 turns. This worked rather better...
Close up of can;
I also managed to launch a can around 2m into the air by standing it just above the coil.
All in all, a fun evening of work! If anyone has any advice on designing a failsafe trigger/charging switch, please let me know.
Registered Member #1107
Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792
hey, welcome to the forum. Can crushing is soo cool and there is a lot that you can do with capacitors. Now for the bad stuff. Those capacitors are not pulse rated and you are probably going to end up blowing them. Another member here used very similar capacitors and one exploded on him. I recommend you getting some aerovox pulse rated capacitors before you continue.
Registered Member #540
Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969
Yeah, those aren't pulse rated caps. Those are for HV DC filtering. Pulse caps have thicker terminals.
I think electrolytic caps can work for some pulse work but I don't think they are very happy with discharging into very low impedance loads (can crushing, wire exploding, etc.).
What are you using to discharge the energy stored in the caps into the load?
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.
800(ish)J Can Crusher
