Welcome
Username or Email:

Password:


Missing Code




[ ]
[ ]
Online
  • Guests: 75
  • Members: 0
  • Newest Member: omjtest
  • Most ever online: 396
    Guests: 396, Members: 0 on 12 Jan : 12:51
Members Birthdays:
All today's birthdays', congrats!
dan (37)
rchydro (64)
CapRack (30)


Next birthdays
11/07 Dave Marshall (40)
11/07 Worms (46)
11/08 Bert (77)
Contact
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.
Forums
4hv.org :: Forums :: General Science and Electronics
« Previous topic | Next topic »   

Trouble with rewound toroidal transformer, never rewound a transformer before

Move Thread LAN_403
radiotech
Sat Apr 18 2015, 01:58PM
radiotech Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
Vacuum tube filaments have large cold to hot resistance ratio, so
a too puny transformer may cause a long warmup time.

This can rapidly damage the emissive surface if full anode voltage is applied
during warmup.

The 10 amp filament transformers I have here will instantly fuse a 22 gauge
wire if accidently shorted across the terminals.

You might scarf some heavy copper wire from an old microwave oven
transformer filament secondary.
Back to top
Download
Sat Apr 18 2015, 02:20PM
Download Registered Member #561 Joined: Sat Mar 03 2007, 02:46AM
Location: Adelaide Australia
Posts: 230
I tested with full load from the GU-48 filament. I forgot to test the voltage but it was 10.4V no load and the filament glowed pretty brightly.

I wound it with 12 or 13 AWG wire. It should be fine and the transformer wasn't in any way hot after 60 seconds of running.

I got 0.08Ohms across the secondary so the voltage drop should be negligible.

Some photos for those interested:

Link2

Link2
Back to top
klugesmith
Sun Apr 19 2015, 06:13AM
klugesmith Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716
I got 0.08Ohms across the secondary so the voltage drop should be negligible.
Agreed, if 0.8 volts is negligible. That's not counting additional voltage drop from primary current x primary winding resistance.

Nice looking transformer you got, esp. as your first rewinding exercise.
And nice to see your GU-48 supported by battery cable clips. Must be convergent evolution. smile

1429423962 2099 FT170584 Vise
Back to top
Download
Sun Apr 19 2015, 11:18AM
Download Registered Member #561 Joined: Sat Mar 03 2007, 02:46AM
Location: Adelaide Australia
Posts: 230
I rather crudely lashed my VTTC together.

Link2

First light:

Link2

No tuning what so ever and I haven't pulled the shunts out of the MOT yet. That I think is for tomorrow. Got about 12" off it at full voltage.

The tube was just cool enough for me to hold after about 30 seconds of running, followed by a break of a few minutes followed by 30 seconds more.

Tuning and shunt pulling after work tomorrow if I feel up to it.
Back to top

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob

Go to:

Powered by e107 Forum System
 
Legal Information
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.