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 #514
Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295
Finally! Two years in the making, here's my new 3.5kVA variac:
230V in, 0-270V out, 15A out... Ah, can't you just taste the power? To keep this monster from tripping the breakers with it's huge inrush current, it has a 50R start-up resistor that is shorted with a 25A contactor two seconds after power-up. Here's a view of the soft-starter:
The casing is made from HDPE (Atleast I think it's HDPE) and lexan. The front and rear covers are steel. It is very heavy, the transformer itself weights over 15kg and the casing probably adds another 5 to it, so you actually need those handles to carry it. It's still more of a "luggable". At the back you can see the two power outputs, each rated at 16A. For things like SSTCs (what else ) that also need a non-variable input, I added a fixed 230V output next to the 0-270V output. They are labeled accordingly, so that should minimize the risk of those nasty wiring errors (Oops, plugged my driver to the variac and bridge directly to mains. Can you say "BOOOM!"?) Here's a view from the top:
And a close-up of the Vout and Iout gauges:
(Yeah, the pics are bad. Photography just ain't my thing, I s'pose) All made from brand new parts, so the cost of all this is... well a lot less than I would have paid for a factory made one.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
I have made a very similar outfit, but with only a voltage meter 0 - 300VAC - in the case.
You have not shewn detail, but my 2KVA variac is fed from an industrial 'yellow box' isolating xfrmr, and has a 'red button' industrial stop switch, an 8A overload trip in addition to Ferraz bottle fuses, TVS diodes backed by gas suppressors, 50 millisecond soft-starter with a Plessey relay in it, and two stage common mode EMI filtration on the input.
Registered Member #514
Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295
Well, compared to that mine is very simple. No isolation transformer, so no isolation from mains. I can always plug it into an isolation transformer, when (if) I finally get a proper one.
It has no mains filter, I couldn't find one that fit into the casing or in my budget. Could I make a suitable one myself?
I was thinking about adding an emergency stop button, but I kind of ran out of space I have a really nice emergency stop switch that is just beggin to be put to use, so maybe I'll think of something.
All in all, it only has very basic protection: input and output fuses and proper grounding, of course.
Oh by the way, this time of the year it smells more like soggy snow and wet.
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.
3.5kVA variac
) that also need a non-variable input, I added a fixed 230V output next to the 0-270V output. They are labeled accordingly, so that should minimize the risk of those nasty wiring errors (Oops, plugged my driver to the variac and bridge directly to mains. Can you say "BOOOM!"?)
I have a really nice emergency stop switch that is just beggin to be put to use, so maybe I'll think of something.