Forums

transformer core flux propagation speed

Started by Jamie M April 13, 2012
On Apr 19, 11:06=A0pm, Phil Hobbs
<pcdhSpamMeSensel...@electrooptical.net> wrote:
> George Herold wrote: > > > On Apr 19, 9:20 pm, Phil Hobbs > > <pcdhSpamMeSensel...@electrooptical.net> wrote: > > > Robert Macy wrote: > > > > > On Apr 19, 6:41 am, Phil Hobbs > > > > <pcdhSpamMeSensel...@electrooptical.net> wrote: > > > > > On 04/19/2012 02:30 AM, Jamie M wrote: > > > > > > > On 4/18/2012 5:55 AM, Robert Macy wrote: > > > > > > >> trigger happy google! > > > > > > >> Anyway, after working with metglas in the micron ranges, I've =
come to
> > > > > >> the conclusion that many magnetic material data sheets are STI=
LL
> > > > > >> showing macro-effects. Refer to the 3C90 data sheet. The data =
sheet
> > > > > >> gives information that is important to you the way you use the=
core
> > > > > >> material but does NOT reflect the true basic nature of magneti=
c
> > > > > >> materials. What has happened is that from reading data sheets, > > > > > >> engineers have gotten a mindset of how magnetism works but tha=
t
> > > > > >> mindset is misleading both as one starts to scale smaller AND =
if one
> > > > > >> tries to use that mindset's understanding to solve some kind o=
f
> > > > > >> performance issue. Instead of really solving a problem, you en=
d up
> > > > > >> optimizing a 'weak' solution. > > > > > > >> It's just that when you see losses and permeability roll off f=
or a
> > > > > >> material, much of those losses and much of that rolloff can be > > > > > >> attributed to conductivity and eddy currents minimizing the fi=
elds
> > > > > >> destroying effective permeability, NOT the true nature of the > > > > > >> material, but rather its gross effectc because of how it's use=
d.
> > > > > >> Again, true these parameters are important to the designer, BE=
CAUSE
> > > > > >> that is the component they're working with, but do not really =
reflect
> > > > > >> the nature of the basic material. > > > > > > >> For example, every one seems to accept that high permeability =
material
> > > > > >> rolls off above some low frequency, like 1MHz, NOT TRUE. the E=
FFECTIVE
> > > > > >> permeability rolls off above 1MHz because of the way the mater=
ial has
> > > > > >> been configured into the form you're using it! *IF* you can ga=
in the
> > > > > >> luxury of restructuring how you use the material you will see =
most
> > > > > >> materials have extremely high permeability above 100MHz > > > > > > >> Sadly, at around 1-2GHz magnetic material is gone due to the m=
oment of
> > > > > >> inertia of the magnetic molecule. > > > > > > > Hi, > > > > > > > Maybe these magnetic monopoles keep their moment of inertia?! > > > > > > >http://news.bbc.co.uk/2/hi/technology/8307804.stm > > > > > > "magnetic monopoles that exist in special crystals known as spi=
n ice"
> > > > > > > cheers, > > > > > > Jamie > > > > > > Another grandstand play by another idiot scientist, so new? =A0Ca=
lling
> > > > > those things monopoles just confuses people, but hey, why not, it=
brings
> > > > > in $$ and invited-speaker gigs. =A0Why worry about accuracy when =
you can
> > > > > have tenure instead? > > > > > > Cheers > > > > > > Phil Hobbs > > > > > Can a true monople come into existance under ANY conceivable > > > > circumstances? > > > > > For example, the suddent creation of charge particles? I mean > > > > creation, too. > > > > If there were really any free magnentic monopoles, they'd eat up > > > magnetic fields the same way that free electric monopoles (e.g. > > > electrons) eat up electric fields. =A0You'd magnetize something, and =
then
> > > within a few minutes it would look as though it were demagnetized, > > > because all its surfaces would be decorated with magnetic monopoles > > > until the field outside went to zero. =A0Just the way ferroelectrics > > > behave in the real world. > > > > Martin is probably much more up on this than I am, but iirc the > > > persistence of intergalactic magnetic fields puts some absurdly low > > > upper limit on the cosmic abundance of magnetic monopoles. > > > > Cheers > > > > Phil Hobbs > > > > -- > > > Dr Philip C D Hobbs > > > Principal Consultant > > > ElectroOptical Innovations LLC > > > Optics, Electro-optics, Photonics, Analog Electronics > > > > 160 North State Road #203 > > > Briarcliff Manor NY 10510 > > > 845-480-2058 > > > > hobbs at electrooptical dot nethttp://electrooptical.net-Hide quoted =
text -
> > > > - Show quoted text - > > > I had this crazy idea (in my youth) that magnetic monopoles would > > obviously occur in pairs and all be bound up like hydrogen atoms. > > Bound up magnetic monopoles might then be dark matter... only x-rays > > or something can break them apart. > > > George H. > > The Big Bang should have done a pretty good job on the intergalactic > ones, then. ;)
Yeah, it's just a crazy idea. And sure if they did exist then there'd be a 'ripple' or something early on in the big bang when they joined together and became 'transparent' to the rest of the stuff. Still if dark matter is ever found and it turns out to be 'bound up' monopoles.... Seems as good a candidate as any of the other dark matter 'particles' But I know squat about particle physics*. George H. *When at Vanderbilt (mid 90's) I sat through numerous particle physics colloquia, the conclusion of every one seemed to be... "And this all agrees with the 'Standard Model'."
> > Cheers > > Phil Hobbs > -- > Dr Philip C D Hobbs > Principal Consultant > ElectroOptical Innovations LLC > Optics, Electro-optics, Photonics, Analog Electronics > > 160 North State Road #203 > Briarcliff Manor NY 10510 > 845-480-2058 > > hobbs at electrooptical dot nethttp://electrooptical.net- Hide quoted tex=
t -
> > - Show quoted text -
On Wed, 18 Apr 2012 19:36:07 -0500, Tim Williams wrote:

> I understand about half the words they use and still grok no understanding
You understand a few more of them than I do, then! I'm still not sure what "grok" means ;-) -- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)
On Apr 21, 8:30=A0am, Fred Abse <excretatau...@invalid.invalid> wrote:
> On Wed, 18 Apr 2012 19:36:07 -0500, Tim Williams wrote: > > I understand about half the words they use and still grok no understand=
ing
> > You understand a few more of them =A0than I do, then! > > I'm still not sure what "grok" means ;-) > > -- > "For a successful technology, reality must take precedence > over public relations, for nature cannot be fooled." > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0(Richard Feynman) Robert Heinlien's "Stranger In a Strangeland"
On Sat, 21 Apr 2012 09:06:11 -0700, Robert Macy wrote:

> On Apr 21, 8:30&#2013266080;am, Fred Abse <excretatau...@invalid.invalid> wrote: >> On Wed, 18 Apr 2012 19:36:07 -0500, Tim Williams wrote: >> > I understand about half the words they use and still grok no >> > understanding >> >> You understand a few more of them &#2013266080;than I do, then! >> >> I'm still not sure what "grok" means ;-) >> >> -- >> "For a successful technology, reality must take precedence over public >> relations, for nature cannot be fooled." &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; >> &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080;(Richard Feynman) > > Robert Heinlien's "Stranger In a Strangeland"
Not my kind of reading. I never liked "science" fiction. -- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)
Fred Abse wrote:
> > On Sat, 21 Apr 2012 09:06:11 -0700, Robert Macy wrote: > > > On Apr 21, 8:30 am, Fred Abse <excretatau...@invalid.invalid> wrote: > >> On Wed, 18 Apr 2012 19:36:07 -0500, Tim Williams wrote: > >> > I understand about half the words they use and still grok no > >> > understanding > >> > >> You understand a few more of them than I do, then! > >> > >> I'm still not sure what "grok" means ;-) > >> > >> -- > >> "For a successful technology, reality must take precedence over public > >> relations, for nature cannot be fooled." > >> (Richard Feynman) > > > > Robert Heinlien's "Stranger In a Strangeland" > > Not my kind of reading. I never liked "science" fiction. > > -- > "For a successful technology, reality must take precedence > over public relations, for nature cannot be fooled." > (Richard Feynman)
SiaSL isn't science fiction, it's half-baked religion. Heinlein was the one that dared L. Ron Hubbard to start Scientology. (For anyone who doesn't know the story, Hubbard bragged that he could make a lot more money by starting a religion than by writing SF. He was quite right, but that shrewdness just about exhausts his admirable qualities.) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
On Sun, 22 Apr 2012 09:17:06 -0400, Phil Hobbs wrote:

> SiaSL isn't science fiction, it's half-baked religion. Heinlein was the > one that dared L. Ron Hubbard to start Scientology.
In that case, I *definitely* want nothing to do with it. -- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)
On Apr 22, 6:17=A0am, Phil Hobbs
<pcdhSpamMeSensel...@electrooptical.net> wrote:
> Fred Abse wrote: > > > On Sat, 21 Apr 2012 09:06:11 -0700, Robert Macy wrote: > > > > On Apr 21, 8:30 am, Fred Abse <excretatau...@invalid.invalid> wrote: > > >> On Wed, 18 Apr 2012 19:36:07 -0500, Tim Williams wrote: > > >> > I understand about half the words they use and still grok no > > >> > understanding > > > >> You understand a few more of them =A0than I do, then! > > > >> I'm still not sure what "grok" means ;-) > > > >> -- > > >> "For a successful technology, reality must take precedence over publ=
ic
> > >> relations, for nature cannot be fooled." > > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0(Richard Feynman) > > > > Robert Heinlien's "Stranger In a Strangeland" > > > Not my kind of reading. I never liked "science" fiction. > > > -- > > "For a successful technology, reality must take precedence > > over public relations, for nature cannot be fooled." > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0 =A0(Richard Feynman)
> > SiaSL isn't science fiction, it's half-baked religion. =A0Heinlein was th=
e
> one that dared L. Ron Hubbard to start Scientology. =A0(For anyone who > doesn't know the story, Hubbard bragged that he could make a lot more > money by starting a religion than by writing SF. =A0He was quite right, > but that shrewdness just about exhausts his admirable qualities.) > > Cheers > > Phil Hobbs > > -- > Dr Philip C D Hobbs > Principal Consultant > ElectroOptical Innovations LLC > Optics, Electro-optics, Photonics, Analog Electronics > > 160 North State Road #203 > Briarcliff Manor NY 10510 > 845-480-2058 > > hobbs at electrooptical dot nethttp://electrooptical.net
Ever notice the parallel between religion and science? Years ago, it was thought that religion answered ALL quesstions. People get lost in religion, and if you don't adhere to the rules, you get branded as a heretic and persecuted and/or drummed out of society. Today, it's thought that science answers ALL questions. People get lost in science, and if you don't adhere to the rules, you get branded 'non-scientific' and persecuted and/or drummed out of ...you get the idea. Wonder what's next? Non-causal, simultaneity?
Robert Macy wrote:
> > On Apr 22, 6:17 am, Phil Hobbs > <pcdhSpamMeSensel...@electrooptical.net> wrote: > > Fred Abse wrote: > > > > > On Sat, 21 Apr 2012 09:06:11 -0700, Robert Macy wrote: > > > > > > On Apr 21, 8:30 am, Fred Abse <excretatau...@invalid.invalid> wrote: > > > >> On Wed, 18 Apr 2012 19:36:07 -0500, Tim Williams wrote: > > > >> > I understand about half the words they use and still grok no > > > >> > understanding > > > > > >> You understand a few more of them than I do, then! > > > > > >> I'm still not sure what "grok" means ;-) > > > > > >> -- > > > >> "For a successful technology, reality must take precedence over public > > > >> relations, for nature cannot be fooled." > > > >> (Richard Feynman) > > > > > > Robert Heinlien's "Stranger In a Strangeland" > > > > > Not my kind of reading. I never liked "science" fiction. > > > > > -- > > > "For a successful technology, reality must take precedence > > > over public relations, for nature cannot be fooled." > > > (Richard Feynman) > > > > SiaSL isn't science fiction, it's half-baked religion. Heinlein was the > > one that dared L. Ron Hubbard to start Scientology. (For anyone who > > doesn't know the story, Hubbard bragged that he could make a lot more > > money by starting a religion than by writing SF. He was quite right, > > but that shrewdness just about exhausts his admirable qualities.) > > > > Cheers > > > > Phil Hobbs > > > > -- > > Dr Philip C D Hobbs > > Principal Consultant > > ElectroOptical Innovations LLC > > Optics, Electro-optics, Photonics, Analog Electronics > > > > 160 North State Road #203 > > Briarcliff Manor NY 10510 > > 845-480-2058 > > > > hobbs at electrooptical dot nethttp://electrooptical.net > > Ever notice the parallel between religion and science? > > Years ago, it was thought that religion answered ALL quesstions. > People get lost in religion, and if you don't adhere to the rules, you > get branded as a heretic and persecuted and/or drummed out of society. > > Today, it's thought that science answers ALL questions. People get > lost in science, and if you don't adhere to the rules, you get branded > 'non-scientific' and persecuted and/or drummed out of ...you get the > idea. > > Wonder what's next? Non-causal, simultaneity?
I wouldn't subscribe to your picture of religion above, but it's perfectly true that we have a number of rather unpleasant modern religions nowadays: scientism (as opposed to science, though there's some overlap in the participants), environmentalism, and anti-humanism. By "environmentalism" I don't mean folks like me, who keep the thermostat turned down, make a point of living close to work, and try not to waste stuff--I mean the folks that think that the sky is falling, that fracturing rock a mile below the ground water level can hurt anything, and (especially) that the planet would be better off without any people on it. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
On Mon, 16 Apr 2012 19:47:49 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>boB wrote: >>=20 >> On 16 Apr 2012 13:18:00 -0500, boB <K7IQ> wrote: >>=20 >> >On Mon, 16 Apr 2012 09:55:21 -0400, Phil Hobbs >> ><pcdhSpamMeSenseless@electrooptical.net> wrote: >> > >> >>On 04/16/2012 12:38 AM, josephkk wrote: >> >>> On Sat, 14 Apr 2012 16:14:26 -0700, Jamie M<jmorken@shaw.ca> =
wrote:
>> >>> >> >>>> On 4/14/2012 12:41 PM, Wimpie wrote: >> >>>>> El 14-04-12 0:15, Jamie M escribi=F3: >> >>>>>> Hi, >> >>>>>> >> >>>>>> I was curious about how fast the winding induced flux will =
propagate
>> >>>>>> through a transformer core (ie a ferrite core) assuming a =
single
>> >>>>>> primary winding on a toroid? Would it be possible to make a =
resonant
>> >>>>>> transformer using core geometry (ie replacing the toroid with a=
shape
>> >>>>>> that has a sine wave on the toroid). If the switching frequency=
is high
>> >>>>>> enough, maybe it is possible to utilize the finite flux =
propagation
>> >>>>>> speed (ie. by using resonant flux switching to give different =
simulated
>> >>>>>> urns ratios etc) >> >>>>>> >> >>>>>> cheers, >> >>>>>> Jamie >> >>>>> >> >>>>> hello Jamie, >> >>>>> >> >>>>> The phenomenon is known, even standing waves in the magnetic =
medium
>> >>>>> because of the air/ferrite boundary. >> >>>>> >> >>>>> Besides high mu_r, ferrite materials have a eps_r> 1, it can =
be>1000
>> >>>>> (MnZn ferrite). This reduces the propagation speed =
significantly.
>> >>>>> unfortunately, most manufacturers don't specify eps_r' and =
eps_r''
>> >>>>> versus frequency for their power ferrites. >> >>>> >> >>>> Hi, >> >>>> >> >>>> Thanks, I guess for experimenting it would be good to find a core >> >>>> material with low propagation speed and also a high saturation =
current
>> >>>> density, maybe MnZn ferrite powder mixed with epoxy to mold it =
into a
>> >>>> custom shape and also increase the saturation current could work?=
I am
>> >>>> not sure about the properties of ferrite compared to =
ferrite+epoxy for a
>> >>>> transformer! >> >>>> >> >>>> cheers, >> >>>> Jamie >> >>>> >> >>> Adding a bunch of lower mu_r and eps_r material interstitially =
will only
>> >>> lower the effective value of mu_r and eps_r. >> >>> >> >>> ?-) >> >>> >> >> >> >>Google "YIG-tuned oscillator design" >> >> >> >>Cheers >> >> >> >>Phil Hobbs >> > >> > >> > >> >At the risk of saying I am hijacking this thread (might need a new >> >topic), what about core noise and dynamic range ?? >> > >> >What I mean is.... If you had a super quiet wide range hall effect >> >or other magnetic sensing device in the gap of a (ferrite ?) core, >> >what would be the smallest AC and/or DC signal change you >> >could see ?? I know there is some noise floor in there but >> >it's kind of hard to read some of the lit I've googled. >> > >> >boB >> > >> > >> > >> > >>=20 >> Actually, I think the noise in ferrite cores was just Johnson noise >> and might get louder with hotter cores maybe but is >> hysteresis maybe an issue too at low low levels ?? >>=20 >> boB >>=20 >> > > >There's also Barkhausen noise, due to the stick-slip motion of magnetic >domains. > >Cheers > >Phil Hobbs
Thank you, i learned something today. ?-)
On 16 Apr 2012 13:38:00 -0500, boB <K7IQ> wrote:

>On 16 Apr 2012 13:18:00 -0500, boB <K7IQ> wrote: > >>On Mon, 16 Apr 2012 09:55:21 -0400, Phil Hobbs >><pcdhSpamMeSenseless@electrooptical.net> wrote: >> >>>On 04/16/2012 12:38 AM, josephkk wrote: >>>> On Sat, 14 Apr 2012 16:14:26 -0700, Jamie M<jmorken@shaw.ca> wrote: >>>> >>>>> On 4/14/2012 12:41 PM, Wimpie wrote: >>>>>> El 14-04-12 0:15, Jamie M escribi=F3: >>>>>>> Hi, >>>>>>> >>>>>>> I was curious about how fast the winding induced flux will =
propagate
>>>>>>> through a transformer core (ie a ferrite core) assuming a single >>>>>>> primary winding on a toroid? Would it be possible to make a =
resonant
>>>>>>> transformer using core geometry (ie replacing the toroid with a =
shape
>>>>>>> that has a sine wave on the toroid). If the switching frequency =
is high
>>>>>>> enough, maybe it is possible to utilize the finite flux =
propagation
>>>>>>> speed (ie. by using resonant flux switching to give different =
simulated
>>>>>>> urns ratios etc) >>>>>>> >>>>>>> cheers, >>>>>>> Jamie >>>>>> >>>>>> hello Jamie, >>>>>> >>>>>> The phenomenon is known, even standing waves in the magnetic =
medium
>>>>>> because of the air/ferrite boundary. >>>>>> >>>>>> Besides high mu_r, ferrite materials have a eps_r> 1, it can =
be>1000
>>>>>> (MnZn ferrite). This reduces the propagation speed significantly. >>>>>> unfortunately, most manufacturers don't specify eps_r' and eps_r'' >>>>>> versus frequency for their power ferrites. >>>>> >>>>> Hi, >>>>> >>>>> Thanks, I guess for experimenting it would be good to find a core >>>>> material with low propagation speed and also a high saturation =
current
>>>>> density, maybe MnZn ferrite powder mixed with epoxy to mold it into=
a
>>>>> custom shape and also increase the saturation current could work? =
I am
>>>>> not sure about the properties of ferrite compared to ferrite+epoxy =
for a
>>>>> transformer! >>>>> >>>>> cheers, >>>>> Jamie >>>>> >>>> Adding a bunch of lower mu_r and eps_r material interstitially will =
only
>>>> lower the effective value of mu_r and eps_r. >>>> >>>> ?-) >>>> >>> >>>Google "YIG-tuned oscillator design" >>> >>>Cheers >>> >>>Phil Hobbs >> >> >> >>At the risk of saying I am hijacking this thread (might need a new >>topic), what about core noise and dynamic range ?? >> >>What I mean is.... If you had a super quiet wide range hall effect >>or other magnetic sensing device in the gap of a (ferrite ?) core, >>what would be the smallest AC and/or DC signal change you >>could see ?? I know there is some noise floor in there but >>it's kind of hard to read some of the lit I've googled. >> >>boB >> > > >And maybe the noise goes up with permeability ? > >I guess I am asking if there are any magnetics >companies that have noise specs for their cores. >I don't believe I have ever seen any from the >usuall sources. > >boB (again) >
I suspect that until someone has sufficient problem with core noise to actually specify the test conditions there won't ever be any. ?-)