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 #1819
Joined: Thu Nov 20 2008, 04:05PM
Location:
Posts: 137
After looking at the specs for the #26 iron powder material from Amidon and other people's remarks on this material, I was wondering if another material could be used with better DC saturation characteristics, lower loss, and lower permeability. The material I was thinking of using is Amidon's #2 material, with a permeability of 10. My question: Would a lower permeability result in a higher magnetization current / energy, and therefore lead to more losses? The core will be used for a high power inductor.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141
There is no 'standard' answer..depends upon the application. What are; - desired inductance - at what average dc current - ac voltage ripple - at what frequency - cooling arrangements (forced-air etc.)
Specifically #26 is good for common-mode rfi filtering it's not good with 100's of kHz even. #2 is commonly used for transformers and inductors in amateur HF designs, due to volume of use it's actually relatively available and cheap. For hobby use where size isn't the main concern, I'd use #2 rather than #26, I use #61 = 4C65 quite a lot, so far so good. I sometimes use MPP cores which are great BUT too expensive. Gapped ferrite is good to 100's of kHz..potentially many MHz.
For any material you're considering, as a quick guide look at the graph that shows Us' and Us'' vs. frequency, Us' is inductive, Us'' is resistive. Where the two cross Q=1 For an inductor I generally aim for Q>>10.
Ultimately design comes down to ensuring average core dissipation is <100mW/cm3 for large cores and <200 mW/cm3 for small cores.
Registered Member #1232
Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881
The optimum grade of iron-powder depends on the application and specifically the required inductance and DC bias conditions it will be subject to.
#52 material (Green/Blue) is a low loss version of the cheap and common type 26 material often found in light dimmers and PC power supplies. In many applications it is a drop-in replacement and will run cooler due to the lower core losses.
Type 2 is good for things like RF power transformers and Radio Frequency Chokes. The carbonyl iron powder is low loss, and has excellent resistance to saturation due to heavy DC bias. The downside is that the permeability is lower so you will need more turns to get the same inductance value. This may mean that copper losses are higher.
Materials like #34 and #35 are somewhere in between. They have a medium permeability and reasonably low core loss. They are often used for things like boost PFC chokes where input ripple is typically quite large. In such applications type 26 would overheat due to excessive core loss, and type 2 would overheat due to excessive loss in the copper windings.
Micrometals website has a good bit of design software on there which lets you compare the designs of magnetic components using different materials and core sizes.
Registered Member #1819
Joined: Thu Nov 20 2008, 04:05PM
Location:
Posts: 137
Thanks for the advice, I was wondering what the green-blue material was. But I still have a couple of questions...
Sulaiman wrote ...
There is no 'standard' answer..depends upon the application. What are; - desired inductance - at what average dc current - ac voltage ripple - at what frequency - cooling arrangements (forced-air etc.)
Specifically #26 is good for common-mode rfi filtering it's not good with 100's of kHz even. #2 is commonly used for transformers and inductors in amateur HF designs, due to volume of use it's actually relatively available and cheap. For hobby use where size isn't the main concern, I'd use #2 rather than #26, I use #61 = 4C65 quite a lot, so far so good. I sometimes use MPP cores which are great BUT too expensive. Gapped ferrite is good to 100's of kHz..potentially many MHz.
For any material you're considering, as a quick guide look at the graph that shows Us' and Us'' vs. frequency, Us' is inductive, Us'' is resistive. Where the two cross Q=1 For an inductor I generally aim for Q>>10.
My inductor is 50 uH ~22 Amp DC, 60 turns on a #2 material T-106 core from Amidon. This will be used as a buck inductor, where the AC ripple is relatively small (expected to be around 1A).
From what I understand, the #2 material core can be used in this inductor configuration. The reason I picked the #2 material at the start is because its permeability barely decreases at the specified DC current and core size. I calculated the DC magnetizing force to be around 264 Oersteds, resulting in an inductance drop of only ~2uH at full rated DC amps. What I'm worried about is that the lower permeability of this material will result in higher magnetization current and therefore wasted energy / loss.
If this loss is greater, would it be significant enough to exceed the core loss limit of 100mW / cm^3?
On a side note, I thought that common-mode AC line filters were made of high-permeability ferrite with a bifilar winding. In the Amidon databook, it says that the #26 material is used for differential mode AC line chokes.
Registered Member #1232
Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881
> My inductor is 50 uH ~22 Amp DC, 60 turns on a #2 material T-106 core from Amidon. This will be used as a buck inductor, where the AC ripple is relatively small (expected to be around 1A).
The only problem I see is that you won't be able to get 60 turns of wire capable of carrying 22A through the ID of a T-106 core. You will probably need to use something like a T-200 to give you enough winding window. It also depends on whether you want to make the inductor with a single layer winding or can tolerate multiple layers?
> On a side note, I thought that common-mode AC line filters were made of high-permeability ferrite with a bifilar winding. In the Amidon databook, it says that the #26 material is used for differential mode AC line chokes.
That is correct. High perm MnZn for common-mode filtering like at the input to SMPSUs. Hydrogen reduced iron-powder for low-frequency differential-mode filtering like in light dimmers.
-Richie,
PS. I'd recommend the design software on Micrometals web site. It will quickly allow you to compare the various design options for DC biased buck chokes and make an informed choice.
Registered Member #1819
Joined: Thu Nov 20 2008, 04:05PM
Location:
Posts: 137
GeordieBoy wrote ...
> My inductor is 50 uH ~22 Amp DC, 60 turns on a #2 material T-106 core from Amidon. This will be used as a buck inductor, where the AC ripple is relatively small (expected to be around 1A).
The only problem I see is that you won't be able to get 60 turns of wire capable of carrying 22A through the ID of a T-106 core. You will probably need to use something like a T-200 to give you enough winding window. It also depends on whether you want to make the inductor with a single layer winding or can tolerate multiple layers?
> On a side note, I thought that common-mode AC line filters were made of high-permeability ferrite with a bifilar winding. In the Amidon databook, it says that the #26 material is used for differential mode AC line chokes.
That is correct. High perm MnZn for common-mode filtering like at the input to SMPSUs. Hydrogen reduced iron-powder for low-frequency differential-mode filtering like in light dimmers.
-Richie,
PS. I'd recommend the design software on Micrometals web site. It will quickly allow you to compare the various design options for DC biased buck chokes and make an informed choice.
I guess I didn't think about that; 10 layers of 60 turns of 24 AWG wire is NOT going to fit.
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.
IP Core Material Selection
