Type 43 material for common-mode choke...

[legg]

On Sat, 26 Sep 2020 17:20:51 -0500, John S <Sophi.2@invalid.org>
wrote:

On 9/26/2020 5:16 PM, legg wrote:
On Sat, 26 Sep 2020 16:54:54 -0400, Joe Gwinn <joegwinn@comcast.net
wrote:

On Sat, 26 Sep 2020 16:13:07 -0400, legg <legg@nospam.magma.ca> wrote:

On Sat, 26 Sep 2020 10:39:50 -0500, John S <Sophi.2@invalid.org
wrote:

On 9/26/2020 10:33 AM, legg wrote:
On Sat, 26 Sep 2020 07:41:41 -0500, amdx <amdx@knology.net> wrote:

On 9/24/2020 8:36 PM, bitrex wrote:
The article here says type 43 NiZn ferrite\'s resistive impedance exceeds
it\'s reactance at about 2MHz

https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.


but I think that\'s a misprint, looks more like 15MHz:

https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg

The data-sheet is here:

https://www.fair-rite.com/43-material-data-sheet/

I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH
common-mode choke for about 3 MHz, the calculator says about 30 turns
should give me that but I\'m unclear if this is an appropriate material

It was my understanding the that the point where u\' and u\" cross on a
permeability curve is where the material Q = 1.

https://www.fair-rite.com/43-material-data-sheet/ On this curve that
is at about 7MHz.
How do I reconcile that with the curve on this page.

https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.
Mikek

There is no such thing as material \'Q\'.

When you assume subjective properties in
magnetics, you make a fool of you and me.

RL


I think the crossing point is where the resistance is equal to the
reactance. No?

If so, then the Q at that point is 1. No?

The material itself doesn\'t have reactance. It does
have a bulk resistivity, but that isn\'t directly
related to core loss effects, though lossy materials
can often be identified by their low bulk resistance.

\"It was my understanding the that the point where u\' and u\"
cross on apermeability curve is where the material Q = 1.\"

- Refers to a graph constructed using measurements performed
on a predifined core shape and turns count, as comparative
reference information for the core material in question.
The graphical contents would change with a different core
shape or winding configuration - shifting this specific \'Q\'
point, without altering the material composition of the core.

Another common graph is for the single-turn bead, which
attempts to reduce winding effects on measurement of the
loss characteristic. Each bead size and shape will still
have its own curves, without alteration in the core
material type.

Anyone can stipulate that a Q factor exists for the relation
between any two measurable quantities. providing that its
definition is presented within the scope of the work.

In a non-resonant circuit, the term has little meaning,
as losses in the core are (non-linearly) dependent on the
amplitude of the peak flux excursion, and many other
inter-related physical factors of the core and winding.

A lot of instruments to measure inductors and capacitors report Q, by
which they mean the ratio of reactance divided by resistance at the
chosen test frequency, well away from resonance.

Joe Gwinn

As long as they tell you what they\'re talking about, then
they can call it anything they want.

Q is not a characteristic of the core material.

RL


Perhaps not. But as soon as you put a wire through the hole it has Q at
some point. What good is the core if it not used?

Graphs ARE available for parts under that specific condition,
and for that use.

The OP, however is refering to a graph for 43 matl, and is only
applicable to a 17mmOD /10mmID / 6mmH test speciment with an
unknown number of turna. Fairite, the mfr of 43 matl, doesn\'t
even bother to offer this part size for sale. It is a lab test
specimen.

The size of the test specimen can vary from one matl data sheet
to the next. None are necessarily commercially-sized parts,
though some manufacturers do use a recognizable part number.

For core material there IS a \'relative loss factor\' which is
specified as a maximum limit value at a test frequency.
There ARE graphs for that - check Magnetics Inc matl data.

RL

 

[legg]

On Sat, 26 Sep 2020 22:51:43 GMT, Steve Wilson <spam@me.com> wrote:

legg <legg@nospam.magma.ca> wrote:

On Sat, 26 Sep 2020 16:54:54 -0400, Joe Gwinn <joegwinn@comcast.net
wrote:

A lot of instruments to measure inductors and capacitors report Q, by
which they mean the ratio of reactance divided by resistance at the
chosen test frequency, well away from resonance.

Joe Gwinn

As long as they tell you what they\'re talking about, then
they can call it anything they want.

Q is not a characteristic of the core material.

RL

Many LCR meters report Q as a ratio of reactance divided by resistance.

For example, the Agilent / Keysight U1733C 100Hz/120Hz/1kHz/10kHz/100kHz
Handheld LCR Meter:

https://literature.cdn.keysight.com/litweb/pdf/U1731-90076.pdf

. . and I\'m sure they\'re very useful in measuring actual components.

If you care to reconstruct the test sample, you might even be able to
replot the graph in the 43 matl\'s data sheet, given sufficient test
frequencies.

Enough of this foolery.

RL

 

[legg]

On Sat, 26 Sep 2020 14:48:19 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <user@example.net> wrote:

The article here says type 43 NiZn ferrite\'s resistive impedance exceeds
it\'s reactance at about 2MHz

https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.

but I think that\'s a misprint, looks more like 15MHz:

https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg

The data-sheet is here:

https://www.fair-rite.com/43-material-data-sheet/

I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH
common-mode choke for about 3 MHz, the calculator says about 30 turns
should give me that but I\'m unclear if this is an appropriate material

I\'ve tested some commercial AC-line CM chokes. I was surprised by how
little normal-mode DC current it takes to saturate the ones I tried.
They seem to assume that all AC loads are exactly DC balanced.

Those made with amorphous materials hold remenant values, that
make testing or part qualification difficult.

RL

 

[Steve Wilson]

legg <legg@nospam.magma.ca> wrote:

On Sat, 26 Sep 2020 22:51:43 GMT, Steve Wilson <spam@me.com> wrote:

legg <legg@nospam.magma.ca> wrote:

On Sat, 26 Sep 2020 16:54:54 -0400, Joe Gwinn <joegwinn@comcast.net
wrote:

A lot of instruments to measure inductors and capacitors report Q, by
which they mean the ratio of reactance divided by resistance at the
chosen test frequency, well away from resonance.

Joe Gwinn

As long as they tell you what they\'re talking about, then they can
call it anything they want.

Q is not a characteristic of the core material.

RL

Many LCR meters report Q as a ratio of reactance divided by resistance.

For example, the Agilent / Keysight U1733C
100Hz/120Hz/1kHz/10kHz/100kHz
Handheld LCR Meter:

https://literature.cdn.keysight.com/litweb/pdf/U1731-90076.pdf

. . and I\'m sure they\'re very useful in measuring actual components.

If you care to reconstruct the test sample, you might even be able to
replot the graph in the 43 matl\'s data sheet, given sufficient test
frequencies.

The U1733C will do that for you. Up to 2GHz. Unfortunately, it is a very
expensive unit.

Enough of this foolery.

RL