Searching for ferrite and iron powder rods or steel laminations for transformer type inductors has led me no where. Can you use toroids to make inductors for speaker x-overs? I'm asking cause I've never seen it done and there might be a very good reason for this.
If I can use it, is iron powder or ferrite better. I've heard that people use iron powder, but most of the iron powder I've seen has very low permability. But it's suppose to be more stable or something.
Here's a picture of what you could call an inductor (inductance .08 mH) that I made out of old washing machine motor. The core is steel laminations and measure 15 cm or 6" across. Any body know why the inductance is so low? I made another one about 1/3 the size to see if this was a fluke and it had an inductance of .01 mH.
If I can use it, is iron powder or ferrite better. I've heard that people use iron powder, but most of the iron powder I've seen has very low permability. But it's suppose to be more stable or something.
Here's a picture of what you could call an inductor (inductance .08 mH) that I made out of old washing machine motor. The core is steel laminations and measure 15 cm or 6" across. Any body know why the inductance is so low? I made another one about 1/3 the size to see if this was a fluke and it had an inductance of .01 mH.
Attachments
If that is a magnet, that may be your problem.
Bet this is looking pretty good right now. 😉
http://www.partsexpress.com/pe/show...79&St3=87597025&DS_ID=3&Product_ID=6941&DID=7
Bet this is looking pretty good right now. 😉
http://www.partsexpress.com/pe/show...79&St3=87597025&DS_ID=3&Product_ID=6941&DID=7
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Perhaps to a sensable individual, but not me.
It's not a magnet it's steel laminations I got from a washing machine motor and painted with primer. I think the bottom layer of windings got cut by the sharp edges of the laminations and that had been messing with my measurement, maybe😕
Ron E, you definately have the deepest quote I've ever read. Really makes me think . . . . who the hell is Nicholas Murray Butler
It's not a magnet it's steel laminations I got from a washing machine motor and painted with primer. I think the bottom layer of windings got cut by the sharp edges of the laminations and that had been messing with my measurement, maybe😕
Ron E, you definately have the deepest quote I've ever read. Really makes me think . . . . who the hell is Nicholas Murray Butler
As regarding your technical question, I am not sure if you can use "just any" toroid - I have never seen one used in a crossover.
Using cores that are not designed for audio work may be a problem, because the permeability varies with frequency.
Nicholas Murray Butler was a College President at Columbia University who wrote a few things and got a Nobel Prize, IIRC
http://www.brainyquote.com/quotes/authors/n/a130455.html
He has another rather profound Quote:
Many peoples' tombstones should read 'Died at thirty, buried at 60.'
Using cores that are not designed for audio work may be a problem, because the permeability varies with frequency.
Nicholas Murray Butler was a College President at Columbia University who wrote a few things and got a Nobel Prize, IIRC
http://www.brainyquote.com/quotes/authors/n/a130455.html
He has another rather profound Quote:
Many peoples' tombstones should read 'Died at thirty, buried at 60.'
I like the first quote better.
I think you're right about those cores. Their U's vary with frequecies. I haven't found any designed for such low frequencies as I am using. Even those partsexpress cores use silicon steel laminations I think. Best thing to use is steel, I think.
I think you're right about those cores. Their U's vary with frequecies. I haven't found any designed for such low frequencies as I am using. Even those partsexpress cores use silicon steel laminations I think. Best thing to use is steel, I think.
Intertechnik makes toroid coils for use in audio crossovers..
http://www.intertechnik.de/cgi-local/shop4/shop4_info.pl?1340592
http://www.intertechnik.de/cgi-local/shop4/shop4_info.pl?1340592
Hi,
Using toroidal cores is possible for x-over inductors. But ferrite toroidal cores are no-no if they have to handle power. You have to use iron powder cores for this with a distributed air gap. Have a look here:
http://www.mag-inc.com/powder/powder_cores.asp
MPP cores and Koolmu is a good choice. But beware these cores are not cheap. Also a wealth of technical and background info on that site.
😎
Using toroidal cores is possible for x-over inductors. But ferrite toroidal cores are no-no if they have to handle power. You have to use iron powder cores for this with a distributed air gap. Have a look here:
http://www.mag-inc.com/powder/powder_cores.asp
MPP cores and Koolmu is a good choice. But beware these cores are not cheap. Also a wealth of technical and background info on that site.
😎
peranders said:
12 mH and the amps I'm not sure of. The inductor is for the lower 20 cm woofer on a 2.5-way, so how ever is the most amount of amps that can be put to the woofer.
I found some toroids . . .
but I don't know if they're suitable for my application. They are 77439-A7 on this page http://www.arnoldmagnetics.com/products/powder/pdf/cross_ref_super_mss.pdf OD - 1.84" ID - .95" Height - .71" Permability 60 (rather low I thnk). I can get 13 of these for $25. So I would like to get atleast 2 mH on one or atleast 4 mH if I stack two of them (second opinion seems easier). Is this possible or a good idea for that matter?
They're made out of this:
SUPER-MSS® utilizes an iron-silicon-aluminum alloy powder which has high resistivity and low magnetostriction. A 10,000 Gauss saturation level provides high energy storage at a lower total loss compared with iron powder or gapped ferrites, and at lower cost than MPP.
but I don't know if they're suitable for my application. They are 77439-A7 on this page http://www.arnoldmagnetics.com/products/powder/pdf/cross_ref_super_mss.pdf OD - 1.84" ID - .95" Height - .71" Permability 60 (rather low I thnk). I can get 13 of these for $25. So I would like to get atleast 2 mH on one or atleast 4 mH if I stack two of them (second opinion seems easier). Is this possible or a good idea for that matter?
They're made out of this:
SUPER-MSS® utilizes an iron-silicon-aluminum alloy powder which has high resistivity and low magnetostriction. A 10,000 Gauss saturation level provides high energy storage at a lower total loss compared with iron powder or gapped ferrites, and at lower cost than MPP.
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