On Fri, 25 Aug 2023 22:56:50 +0100, TTman <kraken.sankey@gmail.com>
wrote:

>
>>>
>>> Cheers
>>>
>>> Phil Hobbs
>>
>> At least tubes had keys. You can load an IC wrong two or four ways.
>> Why are so many things symmetric?
>>
>That 3 way choke doesn't look symmetrical to me in the PCB pin layout.....

It's 3-way, 120 degree, symmetric. But there's no way to install it
wrong... it always works.

On Fri, 25 Aug 2023 08:54:21 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

>On Fri, 25 Aug 2023 09:48:10 -0400, legg <legg@nospam.magma.ca> wrote:
>
>>On Thu, 24 Aug 2023 09:32:25 -0700, John Larkin
>><jlarkin@highlandSNIPMEtechnology.com> wrote:
>>
>>>On Thu, 24 Aug 2023 11:55:35 -0400, legg <legg@nospam.magma.ca> wrote:
>>>
>>>>On Thu, 24 Aug 2023 06:48:48 -0700 (PDT), Anthony William Sloman
>>>><bill.sloman@ieee.org> wrote:
>>>>
>>>>>On Thursday, August 24, 2023 at 12:44:21?PM UTC+10, John Larkin wrote:
>>>>>> This inductor data sheet numbers the six pins, we suspect using a
>>>>>> european third-angle projection, but the part has no hint of where pin
>>>>>> 1 might be.
>>>>>>
>>>>>> https://www.digikey.com/en/products/detail/schaffner-emc-inc/RT8132-8-4M8/8345234
>>>>>>
>>>>>> It doesn't matter, but our production and QC people will pester us
>>>>>> endlessly about it.
>>>>>>
>>>>>> The drawings in the data sheet are inaccurate too.
>>>>>>
>>>>>>
>>>>>> On this connector,
>>>>>>
>>>>>> https://www.digikey.com/en/products/detail/phoenix-contact/1809102/3439835
>>>>>>
>>>>>> https://www.digikey.com/en/products/detail/phoenix-contact/1861726/9349730
>>>>>>
>>>>>> neither the header nor its mate suggests a pin 1, on the data sheet or
>>>>>> on the parts. It matters.
>>>>>
>>>>>Actually, it doesn't. these. These are just common modes chokes on a single core with two or three coils of equal inductance, and they are all wound in the same sense. It doesn't make any difference which way around you mount them, as anybody who understood inductors would know. Explaining this to people who don't understand inductors gets tedious, which is presumably what John Larkin is bitching about.
>>>>
>>>>They're supposed to be idiot-proof, but with EMC, physical
>>>>placement of starts and finishes on the physical body
>>>>can have unexpected benefits/pitfalls.
>>>
>>>The CM choke works at any rotation, as I noted and Sloman ignored. The
>>>only problem is not getting pestered by production and QC, namely
>>>"where is pin 1?" We'll have to note in the production documentation
>>>IT DOESN'T MATTER. We deliberately didn't include a pin1 dot on the
>>>PCB silk.
>>>
>>>Sloman is never pestered by production or QC. His only mission is life
>>>is to tell everyone else how stupid they are.
>>>
>>>
>>>>
>>>>There are only a rare few EMC choke designs that are suitable
>>>>for automated fab, so you're often at the mercy of visual
>>>>inspection of manual windings, for 'internal' lead dressing
>>>>or winding direction, though phasing may be accurate and
>>>>measurable leakage terms by the book.
>>>>
>>>>RL
>>>
>>>The leakage inductance is tiny on that choke, like 15uH on one winding
>>>with the other two shorted. CM chokes tend to use very hi-mu core
>>>material, which means they saturate at very low levels of non-balanced
>>>current. One can be fooled by distributor searches into thinking these
>>>are really good multi-winding conventional inductors.
>>>
>>>I guess they might be good transformers. Hey, maybe I can use a cool
>>>Coilcraft planar transformer instead of that monster.
>>
>>The 18uH leakage inductance is free and works om DM currents. It's
>>also the 'oick-up antenna' for nuisance local EMI re-radiation in
>>just the exact wrong place - in the filter hardware itself - often
>>justifying local physical screening in hardware $ $ $ .
>>
>
>CM chokes are specified for inductance and for max current, which
>seems to be purely thermal.
>
>People never seem to specify actual core saturation currents; looks
>like they assume that the net flux is zero. They typically saturate at
>a few per cent of datasheet current.
>
>One could test the current rating without saturating a 2-wire CM
>choke, but I can't think of a way to test a 3-winding choke without
>saturating the core.

Ferrite cores are thermally limited to < curie temp, with the
higher permeability types having the lowest limits (<110C).

If it's an amorphous core matl, that isn't an issue, but Permeability
drops with current rather rapidly in ungapped structures of any form.

You can run DC current through two windings in a loop with inductive
decoupling while measuring L on the 3rd to get an idea of whats going
on during lower frequency imbalance to your common mode element..

This choke cannot force net zero flux - it merely assumes that there
is no 4th path. If your inverter 'wiggles' are large and low-
frequency, RF will burst through on the peak imbalance.

RL

On Thursday, August 24, 2023 at 9:32:48 AM UTC-7, John Larkin wrote:

> The leakage inductance is tiny on that choke, like 15uH on one winding
> with the other two shorted. CM chokes tend to use very hi-mu core
> material, which means they saturate at very low levels of non-balanced
> current. One can be fooled by distributor searches into thinking these
> are really good multi-winding conventional inductors.
>
> I guess they might be good transformers. Hey, maybe I can use a cool
> Coilcraft planar transformer instead of that monster.

CM chokes can use very lossy magnetic material and still
do their job well; it could be a good transformer if you use
it as a current transformer, but not as an AC voltage source.
Most 'planar transformer' applications DO NOT work well with
lossy magnetics. RF would cook 'em.

On Saturday, August 26, 2023 at 1:54:46 AM UTC+10, John Larkin wrote:
> On Fri, 25 Aug 2023 09:48:10 -0400, legg <le...@nospam.magma.ca> wrote:
>
> >On Thu, 24 Aug 2023 09:32:25 -0700, John Larkin
> ><jla...@highlandSNIPMEtechnology.com> wrote:
> >
> >>On Thu, 24 Aug 2023 11:55:35 -0400, legg <le...@nospam.magma.ca> wrote:
> >>
> >>>On Thu, 24 Aug 2023 06:48:48 -0700 (PDT), Anthony William Sloman
> >>><bill....@ieee.org> wrote:
> >>>
> >>>>On Thursday, August 24, 2023 at 12:44:21?PM UTC+10, John Larkin wrote:
> >>>>> This inductor data sheet numbers the six pins, we suspect using a
> >>>>> european third-angle projection, but the part has no hint of where pin
> >>>>> 1 might be.
> >>>>>
> >>>>> https://www.digikey.com/en/products/detail/schaffner-emc-inc/RT8132-8-4M8/8345234
> >>>>>
> >>>>> It doesn't matter, but our production and QC people will pester us
> >>>>> endlessly about it.
> >>>>>
> >>>>> The drawings in the data sheet are inaccurate too.
> >>>>>
> >>>>>
> >>>>> On this connector,
> >>>>>
> >>>>> https://www.digikey.com/en/products/detail/phoenix-contact/1809102/3439835
> >>>>>
> >>>>> https://www.digikey.com/en/products/detail/phoenix-contact/1861726/9349730
> >>>>>
> >>>>> neither the header nor its mate suggests a pin 1, on the data sheet or
> >>>>> on the parts. It matters.
> >>>>
> >>>>Actually, it doesn't. these. These are just common modes chokes on a single core with two or three coils of equal inductance, and they are all wound in the same sense. It doesn't make any difference which way around you mount them, as anybody who understood inductors would know. Explaining this to people who don't understand inductors gets tedious, which is presumably what John Larkin is bitching about.
> >>>
> >>>They're supposed to be idiot-proof, but with EMC, physical
> >>>placement of starts and finishes on the physical body
> >>>can have unexpected benefits/pitfalls.
> >>
> >>The CM choke works at any rotation, as I noted and Sloman ignored. The
> >>only problem is not getting pestered by production and QC, namely
> >>"where is pin 1?" We'll have to note in the production documentation
> >>IT DOESN'T MATTER. We deliberately didn't include a pin1 dot on the
> >>PCB silk.
> >>
> >>Sloman is never pestered by production or QC. His only mission is life
> >>is to tell everyone else how stupid they are.
> >>
> >>
> >>>
> >>>There are only a rare few EMC choke designs that are suitable
> >>>for automated fab, so you're often at the mercy of visual
> >>>inspection of manual windings, for 'internal' lead dressing
> >>>or winding direction, though phasing may be accurate and
> >>>measurable leakage terms by the book.
> >>>
> >>>RL
> >>
> >>The leakage inductance is tiny on that choke, like 15uH on one winding
> >>with the other two shorted. CM chokes tend to use very hi-mu core
> >>material, which means they saturate at very low levels of non-balanced
> >>current. One can be fooled by distributor searches into thinking these
> >>are really good multi-winding conventional inductors.
> >>
> >>I guess they might be good transformers. Hey, maybe I can use a cool
> >>Coilcraft planar transformer instead of that monster.
> >
> >The 18uH leakage inductance is free and works om DM currents. It's
> >also the 'oick-up antenna' for nuisance local EMI re-radiation in
> >just the exact wrong place - in the filter hardware itself - often
> >justifying local physical screening in hardware $ $ $ .
> >
> CM chokes are specified for inductance and for max current, which
> seems to be purely thermal.
>
> People never seem to specify actual core saturation currents; looks
> like they assume that the net flux is zero. They typically saturate at
> a few per cent of datasheet current.
>
> One could test the current rating without saturating a 2-wire CM
> choke, but I can't think of a way to test a 3-winding choke without
> saturating the core.

Neither could I at 2:19am local time. As soon as I'd gone to bed I realised that three sine waves of identical frequency and amplitude but phased 120 degrees apart would do the job.

The trignometric identity you need to prove it is sin(a+b) = sin(a).cos(b) + sin(b). cos(a)

--
Bill Sloman, Sydney

On Saturday, August 26, 2023 at 3:57:07 PM UTC+10, Anthony William Sloman wrote:
> On Saturday, August 26, 2023 at 1:54:46 AM UTC+10, John Larkin wrote:
> > On Fri, 25 Aug 2023 09:48:10 -0400, legg <le...@nospam.magma.ca> wrote:
> >
> > >On Thu, 24 Aug 2023 09:32:25 -0700, John Larkin
> > ><jla...@highlandSNIPMEtechnology.com> wrote:
> > >
> > >>On Thu, 24 Aug 2023 11:55:35 -0400, legg <le...@nospam.magma.ca> wrote:
> > >>
> > >>>On Thu, 24 Aug 2023 06:48:48 -0700 (PDT), Anthony William Sloman
> > >>><bill....@ieee.org> wrote:
> > >>>
> > >>>>On Thursday, August 24, 2023 at 12:44:21?PM UTC+10, John Larkin wrote:
> > >>>>> This inductor data sheet numbers the six pins, we suspect using a
> > >>>>> european third-angle projection, but the part has no hint of where pin
> > >>>>> 1 might be.
> > >>>>>
> > >>>>> https://www.digikey.com/en/products/detail/schaffner-emc-inc/RT8132-8-4M8/8345234
> > >>>>>
> > >>>>> It doesn't matter, but our production and QC people will pester us
> > >>>>> endlessly about it.
> > >>>>>
> > >>>>> The drawings in the data sheet are inaccurate too.
> > >>>>>
> > >>>>>
> > >>>>> On this connector,
> > >>>>>
> > >>>>> https://www.digikey.com/en/products/detail/phoenix-contact/1809102/3439835
> > >>>>>
> > >>>>> https://www.digikey.com/en/products/detail/phoenix-contact/1861726/9349730
> > >>>>>
> > >>>>> neither the header nor its mate suggests a pin 1, on the data sheet or
> > >>>>> on the parts. It matters.
> > >>>>
> > >>>>Actually, it doesn't. these. These are just common modes chokes on a single core with two or three coils of equal inductance, and they are all wound in the same sense. It doesn't make any difference which way around you mount them, as anybody who understood inductors would know. Explaining this to people who don't understand inductors gets tedious, which is presumably what John Larkin is bitching about.
> > >>>
> > >>>They're supposed to be idiot-proof, but with EMC, physical
> > >>>placement of starts and finishes on the physical body
> > >>>can have unexpected benefits/pitfalls.
> > >>
> > >>The CM choke works at any rotation, as I noted and Sloman ignored. The
> > >>only problem is not getting pestered by production and QC, namely
> > >>"where is pin 1?" We'll have to note in the production documentation
> > >>IT DOESN'T MATTER. We deliberately didn't include a pin1 dot on the
> > >>PCB silk.
> > >>
> > >>Sloman is never pestered by production or QC. His only mission is life
> > >>is to tell everyone else how stupid they are.
> > >>
> > >>
> > >>>
> > >>>There are only a rare few EMC choke designs that are suitable
> > >>>for automated fab, so you're often at the mercy of visual
> > >>>inspection of manual windings, for 'internal' lead dressing
> > >>>or winding direction, though phasing may be accurate and
> > >>>measurable leakage terms by the book.
> > >>>
> > >>>RL
> > >>
> > >>The leakage inductance is tiny on that choke, like 15uH on one winding
> > >>with the other two shorted. CM chokes tend to use very hi-mu core
> > >>material, which means they saturate at very low levels of non-balanced
> > >>current. One can be fooled by distributor searches into thinking these
> > >>are really good multi-winding conventional inductors.
> > >>
> > >>I guess they might be good transformers. Hey, maybe I can use a cool
> > >>Coilcraft planar transformer instead of that monster.
> > >
> > >The 18uH leakage inductance is free and works om DM currents. It's
> > >also the 'oick-up antenna' for nuisance local EMI re-radiation in
> > >just the exact wrong place - in the filter hardware itself - often
> > >justifying local physical screening in hardware $ $ $ .
> > >
> > CM chokes are specified for inductance and for max current, which
> > seems to be purely thermal.
> >
> > People never seem to specify actual core saturation currents; looks
> > like they assume that the net flux is zero. They typically saturate at
> > a few per cent of datasheet current.
> >
> > One could test the current rating without saturating a 2-wire CM
> > choke, but I can't think of a way to test a 3-winding choke without
> > saturating the core.
>
> Neither could I at 2:19am local time. As soon as I'd gone to bed I realised that three sine waves of identical frequency and amplitude but phased 120 degrees apart would do the job.
>
> The trignometric identity you need to prove it is sin(a+b) = sin(a).cos(b) + sin(b). cos(a)

So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself

--
Bill Sloman, Sydney

On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
<bill.sloman@ieee.org> wrote:

>So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself

It must be highly provoking, all that silence.

RL

On Tuesday, August 29, 2023 at 11:17:22 PM UTC+10, legg wrote:
> On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
> <bill....@ieee.org> wrote:
>
> >So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself.
>
> It must be highly provoking, all that silence.

On the contrary, if John Larkin provided more of it, I'd be appreciably happier. On this particular occasion he had come up with a question worth answering, which is rare, so I've missed a rare chance to contribute something constructive.

--
Bill Sloman, Sydney

On Tue, 29 Aug 2023 09:20:09 -0400, legg <legg@nospam.magma.ca> wrote:

>On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
><bill.sloman@ieee.org> wrote:
>
>
>>So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself
>
>It must be highly provoking, all that silence.
>
>RL

The copper-loss based current rating, the thermal rating, can be done
with the windings in series, and ignore saturation. And the series
connction can reveal saturation behavior too, and I guess that's all I
need to know. I'll chip a bit of the core and see if it's ferrite or
powdered iron; it's sure heavy.

Sloman is just an insecure insult generator, and he'd rather insult
than either learn or be right. There's no point on wasting time with
idea-free toads like that.

On Wednesday, August 30, 2023 at 1:20:29 AM UTC+10, John Larkin wrote:
> On Tue, 29 Aug 2023 09:20:09 -0400, legg <le...@nospam.magma.ca> wrote:
>
> >On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
> ><bill....@ieee.org> wrote:
> >
> >
> >>So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself
> >
> > It must be highly provoking, all that silence.
> >
> The copper-loss based current rating, the thermal rating, can be done
> with the windings in series, and ignore saturation. And the series
> connection can reveal saturation behavior too, and I guess that's all I
> need to know. I'll chip a bit of the core and see if it's ferrite or
> powdered iron; it's sure heavy.

What you said - at one point - was

"One could test the current rating without saturating a 2-wire CM choke, but I can't think of a way to test a 3-winding choke without saturating the core."

Neither could I when I first looked at your post, but after I'd slept on it I realised that feeding three phases of the same sine wave, spaced 120 degrees apart would do the same job on a 3-winding choke that two phases spaced 180 degrees apart do on a 2-winding choke.

> Sloman is just an insecure insult generator, and he'd rather insult than either learn or be right.

There's no insult in that particular observation - or at least none that I can detect. I think I learnt something, and I'm tolerably sure that the observation is correct.

> There's no point on wasting time with idea-free toads like that.

That does seem to be an idea that you didn't manage to come up with, so I may not be quite as idea-free as you like to think. I've got a couple of patents - not a many as the seriously creative people I've known - so I'd guess that I'm not entirely idea-free.

Getting help when you need it isn't an ego-boosting exercise, but it can save quite a bit of time.

--
Bill Sloman, Sydney

On Tue, 29 Aug 2023 08:20:06 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

>On Tue, 29 Aug 2023 09:20:09 -0400, legg <legg@nospam.magma.ca> wrote:
>
>>On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
>><bill.sloman@ieee.org> wrote:
>>
>>
>>>So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself
>>
>>It must be highly provoking, all that silence.
>>
>>RL
>
>The copper-loss based current rating, the thermal rating, can be done
>with the windings in series, and ignore saturation. And the series
>connction can reveal saturation behavior too, and I guess that's all I
>need to know. I'll chip a bit of the core and see if it's ferrite or
>powdered iron; it's sure heavy.

If series windings are loaded out of phase, the effect of any
flux imbalance (due to leakage) AND thermals can be monitored
on the third winding.

RL

On Tue, 29 Aug 2023 08:20:06 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

<snip>
> I'll chip a bit of the core and see if it's ferrite or
>powdered iron; it's sure heavy.
>

Judging from the Al values, It is probably ferrite -
amorphous parts would be roughly 10x for same turns
count, but there seems to be a lot of plastic present
in the core volume. Weight suggests amorphous matl.

Iron dust is not used where high permeability is the
criterion.

RL

On Wed, 30 Aug 2023 08:04:49 -0400, legg <legg@nospam.magma.ca> wrote:

>On Tue, 29 Aug 2023 08:20:06 -0700, John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote:
>
>>On Tue, 29 Aug 2023 09:20:09 -0400, legg <legg@nospam.magma.ca> wrote:
>>
>>>On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
>>><bill.sloman@ieee.org> wrote:
>>>
>>>
>>>>So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself
>>>
>>>It must be highly provoking, all that silence.
>>>
>>>RL
>>
>>The copper-loss based current rating, the thermal rating, can be done
>>with the windings in series, and ignore saturation. And the series
>>connction can reveal saturation behavior too, and I guess that's all I
>>need to know. I'll chip a bit of the core and see if it's ferrite or
>>powdered iron; it's sure heavy.
>
>If series windings are loaded out of phase, the effect of any
>flux imbalance (due to leakage) AND thermals can be monitored
>on the third winding.
>
>RL

Given the three separate clumps of windings, the leakage inductance,
one winding measured with the other two shorted, is an impressively
low 15 uH. Seems like common-mode chokes use very hi-mu cores.

In my application, I'd actually appreciate more leakage L as part of
my EMI filters. The waveforms are ghastly.

On Wed, 30 Aug 2023 06:26:43 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

>On Wed, 30 Aug 2023 08:04:49 -0400, legg <legg@nospam.magma.ca> wrote:
>
>>On Tue, 29 Aug 2023 08:20:06 -0700, John Larkin
>><jlarkin@highlandSNIPMEtechnology.com> wrote:
>>
>>>On Tue, 29 Aug 2023 09:20:09 -0400, legg <legg@nospam.magma.ca> wrote:
>>>
>>>>On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
>>>><bill.sloman@ieee.org> wrote:
>>>>
>>>>
>>>>>So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself
>>>>
>>>>It must be highly provoking, all that silence.
>>>>
>>>>RL
>>>
>>>The copper-loss based current rating, the thermal rating, can be done
>>>with the windings in series, and ignore saturation. And the series
>>>connction can reveal saturation behavior too, and I guess that's all I
>>>need to know. I'll chip a bit of the core and see if it's ferrite or
>>>powdered iron; it's sure heavy.
>>
>>If series windings are loaded out of phase, the effect of any
>>flux imbalance (due to leakage) AND thermals can be monitored
>>on the third winding.
>>
>>RL
>
>Given the three separate clumps of windings, the leakage inductance,
>one winding measured with the other two shorted, is an impressively
>low 15 uH. Seems like common-mode chokes use very hi-mu cores.
>
>In my application, I'd actually appreciate more leakage L as part of
>my EMI filters. The waveforms are ghastly.

CM chokes, working with safety-limited capacitor values,
are largely ineffective outside a 150Kz-1mHz range.

The leakage, working on DM currents can use larger capacitors,
if these don't contribute to pick-up loop area. This is in
roughly the same frequency range - but unwise component
values can produce peaking in the suppression band as CM and
DM components react with each other and their series/prallel
combinations.

Have you got a 3 phase LISN? No point in guessing if you can
see effects iteratively.

RL

On Wed, 30 Aug 2023 19:28:19 -0400, legg <legg@nospam.magma.ca> wrote:

>On Wed, 30 Aug 2023 06:26:43 -0700, John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote:
>
>>On Wed, 30 Aug 2023 08:04:49 -0400, legg <legg@nospam.magma.ca> wrote:
>>
>>>On Tue, 29 Aug 2023 08:20:06 -0700, John Larkin
>>><jlarkin@highlandSNIPMEtechnology.com> wrote:
>>>
>>>>On Tue, 29 Aug 2023 09:20:09 -0400, legg <legg@nospam.magma.ca> wrote:
>>>>
>>>>>On Mon, 28 Aug 2023 06:19:40 -0700 (PDT), Anthony William Sloman
>>>>><bill.sloman@ieee.org> wrote:
>>>>>
>>>>>
>>>>>>So I gave John Larkin his answer but he won't notice it because he has got me kill-filed. Sad, when he didn't know enough to work it out for himself
>>>>>
>>>>>It must be highly provoking, all that silence.
>>>>>
>>>>>RL
>>>>
>>>>The copper-loss based current rating, the thermal rating, can be done
>>>>with the windings in series, and ignore saturation. And the series
>>>>connction can reveal saturation behavior too, and I guess that's all I
>>>>need to know. I'll chip a bit of the core and see if it's ferrite or
>>>>powdered iron; it's sure heavy.
>>>
>>>If series windings are loaded out of phase, the effect of any
>>>flux imbalance (due to leakage) AND thermals can be monitored
>>>on the third winding.
>>>
>>>RL
>>
>>Given the three separate clumps of windings, the leakage inductance,
>>one winding measured with the other two shorted, is an impressively
>>low 15 uH. Seems like common-mode chokes use very hi-mu cores.
>>
>>In my application, I'd actually appreciate more leakage L as part of
>>my EMI filters. The waveforms are ghastly.
>
>CM chokes, working with safety-limited capacitor values,
>are largely ineffective outside a 150Kz-1mHz range.
>
>The leakage, working on DM currents can use larger capacitors,
>if these don't contribute to pick-up loop area. This is in
>roughly the same frequency range - but unwise component
>values can produce peaking in the suppression band as CM and
>DM components react with each other and their series/prallel
>combinations.
>
>Have you got a 3 phase LISN? No point in guessing if you can
>see effects iteratively.
>
>RL

I'm not using this on a conventional AC power line. My box is a power
source, a 3-phase permanent-magnet alternator simulator, and it drives
a FADEC shorting/shunt regulator. Simulation shows a 6-amp RMS ground
loop, and the 3-leg CM choke reduces that to 100 mA.

The choke is a horrible beast to put on a PC board.

On Wed, 30 Aug 2023 17:41:54 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

<snip>
>>>Given the three separate clumps of windings, the leakage inductance,
>>>one winding measured with the other two shorted, is an impressively
>>>low 15 uH. Seems like common-mode chokes use very hi-mu cores.
>>>
>>>In my application, I'd actually appreciate more leakage L as part of
>>>my EMI filters. The waveforms are ghastly.
>>
>>CM chokes, working with safety-limited capacitor values,
>>are largely ineffective outside a 150Kz-1mHz range.
>>
>>The leakage, working on DM currents can use larger capacitors,
>>if these don't contribute to pick-up loop area. This is in
>>roughly the same frequency range - but unwise component
>>values can produce peaking in the suppression band as CM and
>>DM components react with each other and their series/prallel
>>combinations.
>>
>>Have you got a 3 phase LISN? No point in guessing if you can
>>see effects iteratively.
>>
>>RL
>
>I'm not using this on a conventional AC power line. My box is a power
>source, a 3-phase permanent-magnet alternator simulator, and it drives
>a FADEC shorting/shunt regulator. Simulation shows a 6-amp RMS ground
>loop, and the 3-leg CM choke reduces that to 100 mA.
>
>The choke is a horrible beast to put on a PC board.

Aviation regs are abundant, so you should look up actual requirements,
standards and test gear.

RL

On Wed, 30 Aug 2023 17:41:54 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

<snip>
>
>I'm not using this on a conventional AC power line. My box is a power
>source, a 3-phase permanent-magnet alternator simulator, and it drives
>a FADEC shorting/shunt regulator. Simulation shows a 6-amp RMS ground
>loop, and the 3-leg CM choke reduces that to 100 mA.
>
>The choke is a horrible beast to put on a PC board.

The alternator, regulator and loads will be a hell of a lot more
difficult to simulate accurately than the interconnecting
filter circuitry.

RL

On Thu, 31 Aug 2023 09:20:14 -0400, legg <legg@nospam.magma.ca> wrote:

>On Wed, 30 Aug 2023 17:41:54 -0700, John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote:
>
><snip>
>>
>>I'm not using this on a conventional AC power line. My box is a power
>>source, a 3-phase permanent-magnet alternator simulator, and it drives
>>a FADEC shorting/shunt regulator. Simulation shows a 6-amp RMS ground
>>loop, and the 3-leg CM choke reduces that to 100 mA.
>>
>>The choke is a horrible beast to put on a PC board.
>
>The alternator, regulator and loads will be a hell of a lot more
>difficult to simulate accurately than the interconnecting
>filter circuitry.
>
>RL

I have a gigantic Spice model. A 25 millisecond sim takes about a half
hour to run.

This is the equivalent FADEC regulator that I drive, a small part of
my overall simulation. It's a terrible load. Motorcycles often have a
similar reg, and some cars have permanent-magnet alternators and do
this too.

https://www.dropbox.com/scl/fi/lk0p4dj4a9dtlw1b2kh6r/Fadec_Box.jpg?rlkey=1hsxoak5xc32ul3ymdb06oh12&raw=1

We spun up some jet-engine-type alternators to see how they behave.
They are poorly specified; even the basics are considered to be
top-secret by the makers.

https://www.dropbox.com/scl/fi/yf1vl8jyrg76wu6cvzepo/DSC04245.JPG?rlkey=8awdpqdxg1eu1adlga911df61&raw=1

https://www.dropbox.com/scl/fi/p06hci6l9ir0upjuukqib/PB180166.JPG?rlkey=5r3wyk5yy01jr89hoeicx5b1j&raw=1