|
Dear OM, I'm interested about various measurements with NanoVNA but now I'm fighting with some fundamental questions not related only to nano VNA. but still unable to find answers, even after reading a lot of articles (for example k9yc, palomar engineers, and not only...)
- when I will try to determine ferrite core material by inductance and AL value, how can I be sure about right frequency for inductance? inductance could vary with frequency (various permeability) and then my AL value calculation could be wrong.
- I read somewhere that chokes need higher AL value then transformers. Why chokes requires higher AL value and transformers lower? It is because in chokes big AL value means high inductance with small amount of winding and wire and then high impedance for common mode currents with good efficiency?
Many thanks for answers, hope I will find an answer even when it is not simple topic ?
sources which I used:
|
Dear OM, I'm interested about various measurements with NanoVNA but now
I'm fighting with some fundamental questions not related only to nano VNA.
but still unable to find answers, even after reading a lot of articles (for
example k9yc, palomar engineers, and not only...)
In determining the material characteristics of a toroidal core, usually a
very low frequency is used. Yes, the initial ? is frequency dependent, but
determination of that is by convention made at a low frequency, usually
between 10 kHz and 100 kHz.
- when I will try to determine ferrite core material by inductance and AL
value, how can I be sure about right frequency for inductance? inductance
could vary with frequency (various permeability) and then my AL value
calculation could be wrong.
I've used the routine outlined in one of the video presentations on the
Fair-Rite site (the first addresses the NANOVNA specifically)
:
- I read somewhere that chokes need higher AL value then transformers. Why
chokes requires higher AL value and transformers lower? It is because in
chokes big AL value means high inductance with small amount of winding and
wire and then high impedance for common mode currents with good efficiency?
Chokes as applied to decoupling common mode (CM) currents present on
transmission lines:
The purpose of the choke is:
1) To present a high-impedance to CM currents
2) To pass differential mode (DM) currents with minimal loss
As such, the choke forms a reflective filter due to the larger inductance.
This require a toroid material with large AL value or high initial ?r.
However, using this type of material for transformers, the AL becomes too
large for a very few windings. Therefore a lower AL and ?r is required for
low-loss transformers.
Many thanks for answers, hope I will find an answer even when it is not
simple topic ?
Poke around on the video tutorials on the Fair-Rite site. There is a lot
of good information there. It's all under "Technical Resources" toward the
bottom of that folder.
sources which I used:
Dave - W?LEV
toggle quoted message
Show quoted text
On Mon, Jul 4, 2022 at 4:56 PM <tomas.geci@...> wrote: Dear OM, I'm interested about various measurements with NanoVNA but now
I'm fighting with some fundamental questions not related only to nano VNA.
but still unable to find answers, even after reading a lot of articles (for
example k9yc, palomar engineers, and not only...)
- when I will try to determine ferrite core material by inductance and AL
value, how can I be sure about right frequency for inductance? inductance
could vary with frequency (various permeability) and then my AL value
calculation could be wrong.
- I read somewhere that chokes need higher AL value then transformers.
Why chokes requires higher AL value and transformers lower? It is because
in chokes big AL value means high inductance with small amount of winding
and wire and then high impedance for common mode currents with good
efficiency?
Many thanks for answers, hope I will find an answer even when it is not
simple topic ?
sources which I used:
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
|
Dear Dave,
many thanks for perfect explanation ?now it makes perfect sense for me, you explained it very well.
I will watch videos you have included. I was more oriented to Amidon materials but FairRite looks more informative and up-to-date, fortunately principles are common.
VY 73
Tomas, OM5AST
|
Amidon buys many of their ferrite offerings from Fair-Rite.
Dave - W?LEV
toggle quoted message
Show quoted text
On Mon, Jul 4, 2022 at 6:34 PM <tomas.geci@...> wrote: Dear Dave,
many thanks for perfect explanation ?now it makes perfect sense for me,
you explained it very well.
I will watch videos you have included. I was more oriented to Amidon
materials but FairRite looks more informative and up-to-date, fortunately
principles are common.
VY 73
Tomas, OM5AST
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
|
Hello
I have very little experience with toroids. I made some RUTHROFF transformers but nothing more. On my cores, I note that the Al is not constant. Is this normal ?
TORUS
====
Outside diameter ? 10 mm
Inner diameter ? ~ 5 mm
height 5mm
Self of 33 turns of ? 0.1 mm
--------------------------------------
Bridge measurement BF Z serie
120Hz: 36.75?H 0.443 Ohms
1kHz: 36.34?H 0.447 Ohm
10kHz: 36.08?H 0.455 Ohms
100kHz: 35.91?H 0.635 Ohms
Self of 21 turns of ? 0.2 mm
--------------------------------------
Bridge measurement BF Z serie
120Hz: 8.081?H 0.0764 Ohms
1kHz: 8.122?H 0.0764 Ohm
10kHz: 8.112?H 0.0771 Ohms
100kHz: 8.084?H 0.112 Ohms
Calculation of aL ? (it-is good ?)
=============
Self 33 turns: 33 nH/turn?
Self 21 turns: 18 nH/turn?
73 QRO
F1AMM (Fran?ois)
|
Hi,
I wrote several articles on nanoVNA measurements.
You can find them in English here:
There's also a part about determening toriods, mu's and AL.
73
Arie PA3A
Op 4-7-2022 om 18:51 schreef tomas.geci@...:
toggle quoted message
Show quoted text
Dear OM, I'm interested about various measurements with NanoVNA but now I'm fighting with some fundamental questions not related only to nano VNA. but still unable to find answers, even after reading a lot of articles (for example k9yc, palomar engineers, and not only...)
- when I will try to determine ferrite core material by inductance and AL value, how can I be sure about right frequency for inductance? inductance could vary with frequency (various permeability) and then my AL value calculation could be wrong.
- I read somewhere that chokes need higher AL value then transformers. Why chokes requires higher AL value and transformers lower? It is because in chokes big AL value means high inductance with small amount of winding and wire and then high impedance for common mode currents with good efficiency?
Many thanks for answers, hope I will find an answer even when it is not simple topic ?
sources which I used:
|
It's a pity that your pages are not in HTML; it would have allowed Chrome to translate them to me in French, online. In English, I can't follow.
thanks anyway
|
Hi,
You can translate it doing the following:
?- Open the document with Adobe Acrobat
- Select the whole text and do copy (Ctrl-C)
- in your navigator go to go to
- In the left panel copy the original text
- In the right panel select your language (i.e French). The translated text will appear there.
- Select the translated text, copy it to your favorite word processor and paste it there.
Now you can correct the translated text to make it more understandable and even you can add the pictures from the origin.
Let me know if you have any difficulty with this.
Regards,
Ignacio EB4APL
toggle quoted message
Show quoted text
El 06/07/2022 a las 15:03, F1AMM escribió: It's a pity that your pages are not in HTML; it would have allowed Chrome to translate them to me in French, online. In English, I can't follow.
thanks anyway
--
El software de antivirus Avast ha analizado este correo electrónico en busca de virus.
|
I have a lot of bad luck with Adobe. I had a CS3 version with Acrobat 8 pro (+ license) but it refuses to work. With Adobe it's hard problems. It is therefore insoluble for me to translate your .pdf and it is a pity.
The EZNEC notice is provided, among other things, in Word (.doc). It's impeccable: I converted it into HTML and Google translated it for me into almost perfect French. At least with Google it works.
|
On Wed, Jul 6, 2022 at 06:03 AM, F1AMM wrote:
It's a pity that your pages are not in HTML; it would have allowed Chrome to
translate them to me in French, online. In English, I can't follow.
Use the deepl translator. It will translate pdf files and keep them in the same format as the original. Attached is a translation to French of one of Arie Kleingeld PA3A English articles Roger Here is
|
On Tue, Jul 5, 2022 at 09:29 PM, F1AMM wrote:
Hello
I have very little experience with toroids. I made some RUTHROFF transformers
but nothing more. On my cores, I note that the Al is not constant. Is this
normal ?
Yes the Al will vary with frequency for ferrite toroids. The reason is that the permeability of the ferrite toroid varies with frequency and the Mix (31,43, 75) etc. has a significant effect. Powdered iron Al only varies slightly with frequency. Most of the online ferrite toroid calculators only provide good results at low frequencies. Here is an excellent online calculator for you to try >> Roger
|
I found this online (
):
[image: image.png]
As with air wound inductors, the inductance for fixed ?r, the inductance
varies as the square of the number of turns. The ? in the above equations
should be the ?r of the toroid material times ?o (of free space).
So the scaling between 33 turns and 21 turns would be [21 / 33]^2 or
0.401. If you measured 36 ?H with 33 turns, you should have 33 ?H x 0.401
= 13.4 ?H with 21 turns. Of course, the 33 turns is with 0.1 mm and the 21
?H is with 0.2 mm. But with a larger core, I would expect greater
inductance than the original 0.1 mm core.
Bear in mind that the tolerance in ?r from unit-to-unit may be as much as
20%. This is quite normal even with toroids from the same batch from the
manufacturer.
Dave - W?LEV
toggle quoted message
Show quoted text
On Wed, Jul 6, 2022 at 4:29 AM F1AMM <18471@...> wrote: Hello
I have very little experience with toroids. I made some RUTHROFF
transformers but nothing more. On my cores, I note that the Al is not
constant. Is this normal ?
TORUS
====
Outside diameter ? 10 mm
Inner diameter ? ~ 5 mm
height 5mm
Self of 33 turns of ? 0.1 mm
--------------------------------------
Bridge measurement BF Z serie
120Hz: 36.75?H 0.443 Ohms
1kHz: 36.34?H 0.447 Ohm
10kHz: 36.08?H 0.455 Ohms
100kHz: 35.91?H 0.635 Ohms
Self of 21 turns of ? 0.2 mm
--------------------------------------
Bridge measurement BF Z serie
120Hz: 8.081?H 0.0764 Ohms
1kHz: 8.122?H 0.0764 Ohm
10kHz: 8.112?H 0.0771 Ohms
100kHz: 8.084?H 0.112 Ohms
Calculation of aL ? (it-is good ?)
=============
Self 33 turns: 33 nH/turn?
Self 21 turns: 18 nH/turn?
73 QRO
F1AMM (Fran?ois)
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
|
Hi Roger,
Which Acrobat version are you using to open this file and others generated by the deepl translator? I have version 9 Pro Extended and it refuses to open it, saying that an updated version is needed. Checking with the Acrobat update function it says that there is not any update available.
Regards,
Ignacio
toggle quoted message
Show quoted text
El 06/07/2022 a las 18:10, Roger Need via groups.io escribió: On Wed, Jul 6, 2022 at 06:03 AM, F1AMM wrote:
It's a pity that your pages are not in HTML; it would have allowed Chrome to
translate them to me in French, online. In English, I can't follow.
Use the deepl translator. It will translate pdf files and keep them in the same format as the original.
Attached is a translation to French of one of Arie Kleingeld PA3A English articles
Roger
Here is
--
El software de antivirus Avast ha analizado este correo electrónico en busca de virus.
|
On Wed, Jul 6, 2022 at 10:06 AM, EB4APL wrote: Which Acrobat version are you using to open this file and others
generated by the deepl translator? I have version 9 Pro Extended and it
refuses to open it, saying that an updated version is needed. Checking
with the Acrobat update function it says that there is not any update
available.
It opens fine on one of my old computer using Adobe Reader 11 and also with the latest version of Adobe Reader DC for Windows. Roger
|
Arie Kleingeld PA3A
Roger Need
