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 #1321
Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843
I finally got my new Micro100 carbide grooving tool (and it seems to work very well), so I'm about ready to start experimenting with "pie" type windings.
The issue I'm struggling with is: What's the best way to run the wire connecting the sequential "pies" together; i.e., to get from the top of the most recently wound coil, to the bottom layer of the next groove)?
I seem to recall a lengthy discussion here about the subject, but I can't find that thread.
Was there any consensus on what's the best mechanical method to do it, e.g., by cutting an angled "slit" in the "lands" between grooves?
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
I've just looked at three 1930s RF chokes for you. Two had 45 deg slots cut in the partitions, and one had partitions like cog teeth to reduce the amount of ebonite dielectric between windings, so no special channel had to be cut to lead the wire into the next winding space.
Later RF transmitter chokes used self-supporting wave windings with air 'partitions' between windings, to keep the inter-winding capacitance as low as possible.
Registered Member #93
Joined: Thu Feb 09 2006, 04:11PM
Location: Houston, Texas
Posts: 64
Which grooving tool did you purchase? I took a look at the Micro100 catalog and am wondering about what type of machine the grooving tools are supposed to be mounted in. Would you elaborate on the tool and the type of material you're planning to cut the grooves in?
I've used a table saw to cut circular grooves in UHMW tubes to create pies, but would be interested in anything that's safer.
When I did the winding, I wound on every other pie. I cut notches in the pies so I could run wire from the top of one winding, through a notch, along the unwound path, through the next notch to the bottom of the next winding. It's a potential waste of space, but it was very effective in isolating the windings. One of the reasons I'm asking about the tool is that I would like a way to minimize the width of the routing channels as opposed to the width of the winding channels.
Registered Member #1321
Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843
@RickR:
What I got from Micro100 is a brazed, micrograin carbide, lathe toolbit, part #GS-122002. (I just have a crappy - and I mean crappy - little Micromark 7x14 mini-lathe).
The bits come in different sizes. The one I got cuts a 1/8" wide radial groove (actually 0.122 inches) and it has a 3/8" square shank. It cuts cpvc really well...no grabbing, no melting, no nuthin'...just an easy, precise, nice looking cut.
I wonder what's the best way to cut an angled slit in the "lands" (the partition betweer the winding grooves)? I'm trying to think of how to do it in a precise way, and I'm having trouble.
@Proud Mary:
I'm having trouble trying to visualize the "cog tooth" scheme you're describing.
Registered Member #1321
Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843
Wow look at those things! Thanks...but you didn't need to rob a museum just for my sake...
Anyway, all kidding aside, I see the things you're talking about, and I can see how that design would reduce the capacitive coupling between sections somewhat, however, it isn't clear to me how you can "insulate" the wire to prevent dielectric breakdown as the wire goes from the top of one section to the bottom of the next.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
jpsmith123 wrote ...
Anyway, all kidding aside, I see the things you're talking about, and I can see how that design would reduce the capacitive coupling between sections somewhat, however, it isn't clear to me how you can "insulate" the wire to prevent dielectric breakdown as the wire goes from the top of one section to the bottom of the next.
How do you imagine the potential difference would be distributed down the length of the choke?
Registered Member #1321
Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843
Well the item at issue is a proposed HV secondary, producing approximately 10 kv peak, with 8 sections, so the potential difference across each section, bottom layer to top layer, will be approximately 1250 volts.
The object is to get the winding wire from the top layer of section N to the bottom layer of section N+1, while staying comfortably away from the other layers, and interposing some insulating material therebetween.
Maybe I'm misunderstanding something, but it's not clear to me how a cog tooth partition between adjacent sections can solve this problem.
Registered Member #1321
Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843
One problem is that I don't have a data sheet for this 26 gauge magnet wire I'd like to use, so I'm not sure what its breakdown voltage is.
Of course I searched the internet to get an idea of the range of breakdown voltages available in commercial magnet wire, and IIRC, the lowest rated wire I found was specified as "> 1 KV". (I was surprised to see that some magnet wire was rated at 5 KV, and I think there was some rated even higher).
In any case, to be prudent, I'm assuming my magnet wire is rated at 1 KV. Using this number, I can see that I need to be somewhat careful, but I don't need to get carried away.
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.
Grooved Bobbins For Segmented Windings
