Ferrite Inductor Tolerance
in [Design]
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From: Ian Bell on 14 Jun 2010 19:07 On 14/06/10 15:50, Joerg wrote: > Ian Bell wrote: >> On 14/06/10 01:51, Joerg wrote: >>> Ian Bell wrote: >>>> On 13/06/10 21:26, Joerg wrote: >>>>> Ian Bell wrote: >>>>>> On 13/06/10 16:02, Joerg wrote: >>>>>>> Ian Bell wrote: >>>>>>>> On 12/06/10 23:00, Joerg wrote: >>>>>>>>> Ian Bell wrote: >>>>>>>>>> On 12/06/10 16:07, John Larkin wrote: >>>>>>>>>>> On Sat, 12 Jun 2010 10:22:59 +0100, Ian >>>>>>>>>>> Bell<ruffrecords(a)yahoo.com> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> When winding modest inductors of a few hundred milliHenries on a >>>>>>>>>>>> ferrite >>>>>>>>>>>> core, given Al and a number of turns, what is the typical >>>>>>>>>>>> tolerance on >>>>>>>>>>>> the actual value of inductance when these are made in quantity? >>>>>>>>>>>> >>>>>>>>>>>> Cheers >>>>>>>>>>>> >>>>>>>>>>>> Ian >>>>>>>>>>> >>>>>>>>>>> An ungapped ferrite core could be all over the place. 25% >>>>>>>>>>> wouldn't >>>>>>>>>>> surprise me. They will vary with temperature, too. You can buy >>>>>>>>>>> gapped >>>>>>>>>>> pot cores in tolerances around 2-5%, I think. Or use a pot core >>>>>>>>>>> with a >>>>>>>>>>> slug adjuster if you need 1% or better. See the datasheets. >>>>>>>>>>> >>>>>>>>>>> Powder-type cores can be bought with better tolerances. >>>>>>>>>>> >>>>>>>>>>> The people who wind inductors commercially get the exact >>>>>>>>>>> number of >>>>>>>>>>> turns every time. >>>>>>>>>>> >>>>>>>>>>> John >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> It seems to me there are quite a few factors that could affect the >>>>>>>>>> actual inductance achieved and perhaps the least of them is the >>>>>>>>>> accuracy >>>>>>>>>> in counting the number of turns. I would expect there to be some >>>>>>>>>> tolerance in the Al value of the ferrite, that its exact >>>>>>>>>> dimensions >>>>>>>>>> would have an effect along with how neatly or otherwise the turns >>>>>>>>>> are >>>>>>>>>> wound. I have absolutely no idea if these are the major factors >>>>>>>>>> nor of >>>>>>>>>> the likely size of the actual major factors affecting the actual >>>>>>>>>> inductance. I am just trying to get a feel for the likely >>>>>>>>>> tolerance of >>>>>>>>>> ready made inductors. >>>>>>>>>> >>>>>>>>>> The reason I ask is am am designing some passive audio filters >>>>>>>>>> and I >>>>>>>>>> know exactly what tolerance of resistance and capacitance I can >>>>>>>>>> obtain >>>>>>>>>> but not a clue about inductance. It is no good me using 1% >>>>>>>>>> capacitors >>>>>>>>>> and resistors if inductors normally fail to achieve 5%. >>>>>>>>>> >>>>>>>>> >>>>>>>>> You can get 5% catalog inductors from Delevan, Miller, TDK and >>>>>>>>> several >>>>>>>>> others. If it needs to be more precise then you'd be off to >>>>>>>>> boutique >>>>>>>>> lines, meaning $$$. >>>>>>>>> >>>>>>>>> Example: >>>>>>>>> >>>>>>>>> http://www.delevan.com/seriesPDFs/1782.pdf >>>>>>>>> >>>>>>>> >>>>>>>> Those devices seem to be in the sub milliHenry range, the one I >>>>>>>> need are >>>>>>>> in the humfreds of milliHenries. >>>>>>>> >>>>>>> >>>>>>> Then you'll likely have to live with 5%, for example: >>>>>>> >>>>>>> http://www.yuden.co.jp/us/product/pdf/elhl_e.pdf >>>>>>> >>>>>>> There are other ideas but you'd have to let us know about the >>>>>>> nature of >>>>>>> the product. Things such as yearly qty, why it must be passive, how >>>>>>> many >>>>>>> inductors per unit, whether end-test trimming is ok, et cetera. >>>>>>> Otehrwise it'll all be speculation. >>>>>>> >>>>>> >>>>>> Thanks for the input but I think you have misunderstood me. I already >>>>>> have a source of suitable inductors. What I am interested in is the >>>>>> factors that govern the tolerance of a production inductor (as it >>>>>> comes >>>>>> off the line and before any selection process) and what the resultant >>>>>> overall tolerance is likely to be for inductors around 1H. I am not >>>>>> asking for help designing a product or in selecting parts. >>>>>> >>>>> >>>>> Having designed several custom inductors and transformers, the largest >>>>> tolerance contribution came from the core material. Not the dimensions, >>>>> those are very precise, but from the materials properties. >>>>> >>>> >>>> Thanks Joerg, that is exactly the sort of thing I was looking for. I >>>> have heard the Al can vary by 20% for some core types. has this been >>>> your experience too? >>>> >>> >>> Yes, 20% is quite common, often 30%. It depends on where you get the >>> core material from. It can be quite constant for hundreds of cores and >>> then all of a sudden there is a jump to another value. IOW, you cannot >>> rely on measurements and extrapolate. At least not for longer or larger >>> production runs. >>> >> >> Very interesting Joerg. I have also heard some winders over wind then >> remove turns until the correct inductance is achieved. >> > > Yes, I did that as well. Just had gotten my first PC in the 80's and a > friend had a crude piece of software that acted like a spreadsheet, > under DOS and all text-based. This allowed to enter a formula, measure, > enter the number of wound turns and it would tell me how many to remove > to get to the target inductance. Took a long time to calculate (until I > forked over a serious chunk of cash for a Cyrix math coprocessor), today > it would probably be under a millisecond :-) > LOL Cheers Ian
From: krw on 14 Jun 2010 19:15 On Mon, 14 Jun 2010 04:51:39 -0700, Archimedes' Lever <OneBigLever(a)InfiniteSeries.Org> wrote: >On Mon, 14 Jun 2010 03:10:01 -0400, "Michael A. Terrell" ><mike.terrell(a)earthlink.net> wrote: > >> >>"krw(a)att.bizzzzzzzzzzzz" wrote: >>> >>> On Sun, 13 Jun 2010 14:50:22 -0700, Archimedes' Lever >>> <OneBigLever(a)InfiniteSeries.Org> wrote: >>> >>> >On Sun, 13 Jun 2010 14:43:31 -0700, Joerg <invalid(a)invalid.invalid> >>> >wrote: >>> > >>> >>krw(a)att.bizzzzzzzzzzzz wrote: >>> >>> On Sun, 13 Jun 2010 14:08:03 -0700, Joerg <invalid(a)invalid.invalid> wrote: >>> >>> >>> >>>> Archimedes' Lever wrote: >>> >>>>> On Sun, 13 Jun 2010 13:24:21 -0700, Joerg <invalid(a)invalid.invalid> >>> >>>>> wrote: >>> >>>>> >>> >>>>>> Oh, and how do you suppose you get an "original design" into production >>> >>>>>> without an ECO? >>> >>>>> >>> >>>>> You must also be an acronymical retard as well. >>> >>>>> >>> >>>>> There is a difference between a design release and a change order of an >>> >>>>> existing design. >>> >>>>> >>> >>>> So you guys release new designs without due ECO process? I sure hope you >>> >>>> don't design anything that can harm people. >>> >>> >>> >>> AlwaysWrong doesn't design anything, so no he doesn't release ECOs. Everyone >>> >>> else here who does, uses an ECO process, certainly. >>> >> >>> >> >>> >>Yup. >>> >> >>> >>Maybe they have a different release process for new stuff even though it >>> >>typically _changes_ a product from previous to next generation. Having >>> >>two different release processes doesn't strike me as particularly smart, >>> >>but who knows :-) >>> > >>> > ECO is NOT for a "release", and not all releases are next gen designs >>> >of previous work, idiot. >>> >>> AlwaysWrong is , *SURPRISE*, wrong again. It is an engineering change to the >>> database so an Engineering Change Order is necessary. It's really that >>> simple, AlwaysWrong. You should know simple, by mirror. >>> >>> > Two proofs that you are chasing your own tail. >>> >>> DimBulb just can't avoid the hind-end references. >> >> >> If his parents had read that last ECO, dimmie would have been born >>human. :( > > Said the utter retard that claims to be such a patriot, yet makes >stupid remarks like this about people. Wow! You're reaching for that one DimBulb! > You are not a patriot, dumbfuck, you are the antithesis of patriotism. ....and you say that you're a Christian! Yikes!
From: Michael A. Terrell on 14 Jun 2010 19:45 "krw(a)att.bizzzzzzzzzzzz" wrote: > > On Mon, 14 Jun 2010 04:51:39 -0700, Archimedes' Lever > <OneBigLever(a)InfiniteSeries.Org> wrote: > > >On Mon, 14 Jun 2010 03:10:01 -0400, "Michael A. Terrell" > ><mike.terrell(a)earthlink.net> wrote: > > > >> > >>"krw(a)att.bizzzzzzzzzzzz" wrote: > >>> > >>> On Sun, 13 Jun 2010 14:50:22 -0700, Archimedes' Lever > >>> <OneBigLever(a)InfiniteSeries.Org> wrote: > >>> > >>> >On Sun, 13 Jun 2010 14:43:31 -0700, Joerg <invalid(a)invalid.invalid> > >>> >wrote: > >>> > > >>> >>krw(a)att.bizzzzzzzzzzzz wrote: > >>> >>> On Sun, 13 Jun 2010 14:08:03 -0700, Joerg <invalid(a)invalid.invalid> wrote: > >>> >>> > >>> >>>> Archimedes' Lever wrote: > >>> >>>>> On Sun, 13 Jun 2010 13:24:21 -0700, Joerg <invalid(a)invalid.invalid> > >>> >>>>> wrote: > >>> >>>>> > >>> >>>>>> Oh, and how do you suppose you get an "original design" into production > >>> >>>>>> without an ECO? > >>> >>>>> > >>> >>>>> You must also be an acronymical retard as well. > >>> >>>>> > >>> >>>>> There is a difference between a design release and a change order of an > >>> >>>>> existing design. > >>> >>>>> > >>> >>>> So you guys release new designs without due ECO process? I sure hope you > >>> >>>> don't design anything that can harm people. > >>> >>> > >>> >>> AlwaysWrong doesn't design anything, so no he doesn't release ECOs. Everyone > >>> >>> else here who does, uses an ECO process, certainly. > >>> >> > >>> >> > >>> >>Yup. > >>> >> > >>> >>Maybe they have a different release process for new stuff even though it > >>> >>typically _changes_ a product from previous to next generation. Having > >>> >>two different release processes doesn't strike me as particularly smart, > >>> >>but who knows :-) > >>> > > >>> > ECO is NOT for a "release", and not all releases are next gen designs > >>> >of previous work, idiot. > >>> > >>> AlwaysWrong is , *SURPRISE*, wrong again. It is an engineering change to the > >>> database so an Engineering Change Order is necessary. It's really that > >>> simple, AlwaysWrong. You should know simple, by mirror. > >>> > >>> > Two proofs that you are chasing your own tail. > >>> > >>> DimBulb just can't avoid the hind-end references. > >> > >> > >> If his parents had read that last ECO, dimmie would have been born > >>human. :( > > > > Said the utter retard that claims to be such a patriot, yet makes > >stupid remarks like this about people. > > Wow! You're reaching for that one DimBulb! No kidding. I think 'barncat' has had one too many poisoned mice. > > You are not a patriot, dumbfuck, you are the antithesis of patriotism. > > ...and you say that you're a Christian! Yikes! A wolf in his mommies panties? -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
From: John Larkin on 14 Jun 2010 20:01 On Mon, 14 Jun 2010 18:15:09 -0500, "krw(a)att.bizzzzzzzzzzzz" <krw(a)att.bizzzzzzzzzzzz> wrote: >On Mon, 14 Jun 2010 04:51:39 -0700, Archimedes' Lever ><OneBigLever(a)InfiniteSeries.Org> wrote: > >>On Mon, 14 Jun 2010 03:10:01 -0400, "Michael A. Terrell" >><mike.terrell(a)earthlink.net> wrote: >> >>> >>>"krw(a)att.bizzzzzzzzzzzz" wrote: >>>> >>>> On Sun, 13 Jun 2010 14:50:22 -0700, Archimedes' Lever >>>> <OneBigLever(a)InfiniteSeries.Org> wrote: >>>> >>>> >On Sun, 13 Jun 2010 14:43:31 -0700, Joerg <invalid(a)invalid.invalid> >>>> >wrote: >>>> > >>>> >>krw(a)att.bizzzzzzzzzzzz wrote: >>>> >>> On Sun, 13 Jun 2010 14:08:03 -0700, Joerg <invalid(a)invalid.invalid> wrote: >>>> >>> >>>> >>>> Archimedes' Lever wrote: >>>> >>>>> On Sun, 13 Jun 2010 13:24:21 -0700, Joerg <invalid(a)invalid.invalid> >>>> >>>>> wrote: >>>> >>>>> >>>> >>>>>> Oh, and how do you suppose you get an "original design" into production >>>> >>>>>> without an ECO? >>>> >>>>> >>>> >>>>> You must also be an acronymical retard as well. >>>> >>>>> >>>> >>>>> There is a difference between a design release and a change order of an >>>> >>>>> existing design. >>>> >>>>> >>>> >>>> So you guys release new designs without due ECO process? I sure hope you >>>> >>>> don't design anything that can harm people. >>>> >>> >>>> >>> AlwaysWrong doesn't design anything, so no he doesn't release ECOs. Everyone >>>> >>> else here who does, uses an ECO process, certainly. >>>> >> >>>> >> >>>> >>Yup. >>>> >> >>>> >>Maybe they have a different release process for new stuff even though it >>>> >>typically _changes_ a product from previous to next generation. Having >>>> >>two different release processes doesn't strike me as particularly smart, >>>> >>but who knows :-) >>>> > >>>> > ECO is NOT for a "release", and not all releases are next gen designs >>>> >of previous work, idiot. >>>> >>>> AlwaysWrong is , *SURPRISE*, wrong again. It is an engineering change to the >>>> database so an Engineering Change Order is necessary. It's really that >>>> simple, AlwaysWrong. You should know simple, by mirror. >>>> >>>> > Two proofs that you are chasing your own tail. >>>> >>>> DimBulb just can't avoid the hind-end references. >>> >>> >>> If his parents had read that last ECO, dimmie would have been born >>>human. :( >> >> Said the utter retard that claims to be such a patriot, yet makes >>stupid remarks like this about people. > >Wow! You're reaching for that one DimBulb! > >> You are not a patriot, dumbfuck, you are the antithesis of patriotism. > >...and you say that you're a Christian! Yikes! That's the scary part. Does he abuse people and say s**t and f**k every other word when he's in Church? John
From: Joerg on 14 Jun 2010 20:12
John Larkin wrote: > On Mon, 14 Jun 2010 18:15:09 -0500, "krw(a)att.bizzzzzzzzzzzz" > <krw(a)att.bizzzzzzzzzzzz> wrote: > >> On Mon, 14 Jun 2010 04:51:39 -0700, Archimedes' Lever >> <OneBigLever(a)InfiniteSeries.Org> wrote: [...] >>> You are not a patriot, dumbfuck, you are the antithesis of patriotism. >> ...and you say that you're a Christian! Yikes! > > That's the scary part. Does he abuse people and say s**t and f**k > every other word when he's in Church? > I can't imagine any true believer doing that. But they also would not do it outside church. Ok, we are all fallible and when a wrench breaks off and I bust my knuckle one of those nasty words may slip my lips. But I simply won't call people bad names, that would be hardcore un-Christian. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |