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 #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I think the high primary current is due to NST core saturation, disconnect any load from the secondary slowly raise the primary voltage whilst monitoring the primary current, somewhere near rated input voltage (200 vac) the primary current will start to rise rapidly for a small increase in input voltage. Operate at an input voltage below this point or you will just be heating the primary.
Connect a couple of 1N4001 or similar/better across your dmm (anti-parallel) to measure secondary current without risk of dmm damage.
Registered Member #76
Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458
no, the core does not saturate. on 200 volt input i have a primary current of 0,5A without load on the secondary. on 230volt i have a primary current of 0,7A without load on the secondary, no indicators of core saturation.
for current measurement, can i use a current transformer (ie 1:1000)to measure the safe way? any expierience in this?
Registered Member #52
Joined: Thu Feb 09 2006, 04:22AM
Location: Austin TX
Posts: 57
You should be able to put a load resistor across the current transformer and measure the voltage across the resistor. Use ohm's law to calculate the current across the resistor and multiply by the turns ratio.
i = v / r * n
Using a 1K resistor and a 1:1000 CT should give you 1 volt / amp.
I've always run the wire that I'm measuring through a plastic tube to insulate it from the CT.
Registered Member #76
Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458
what can i use as the core for the current transformer? its 50hz, would a amidon ferrite core (iron powder) core work? or should i use a small iron transformer for it?
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.
2,5kW NST
