mzzj: kiitti/thanks for the link to the Micrometals design software, the user interface is horrible but otherwise it's quite usable, T200-2 was one of the "ok" cores it listed when I plugged in the numbers.
Gapped or those others, umm, theoretically yes right away!, except - where can you get them at <20 pieces per order and off the shelf (i.e. not custom design). I know only Muuntosähkö / www.Trafox.fi around here in Finland that is willing to sell ferrite components for non-corporate customers, but they have a minimum order and the stuff gets quite expensive for gapped. I was and am going for Txxx-2 etc since the local Suomen Radioamatööritarvike has them. They also have ferrites but they're mainly low power and for radio amateur RF works. Places like RS, Farnell, Mouser, just totally suck at anything even remotely magnetic and >1W.
hmm, Mzzj would you know any other places that sell ferrite around here for "hobbyists"?
Genomerics: your air gap calculation looks deceptively simple... there's probably a bug somewhere ;-) Inductance depends on air gap size, and most field energy is stored in the air gap so I'd think one would start the calcs from the max energy (which however depends on inductance also, so this is an iterative mess..?). IIRC there's also a chapter on this in Abraham Pressmans book. I've never bothered to calculate these, it just makes your head hurt
IMHO it's simpler to slap on the minimum number of turns, then pull apart core halves by what looks "ok" and put paper or teflon sheet or whatever in between, then check the inductance and add more turns if necessary, and test the whole thing, and if it works fine, just copy the design. 😀
wrenchone: there were some Micrometals charts about (unless I misinterpreted them) core detoriation, at my specs apparently well above 100k hours of use before core goes exponential. Good to know about Micrometals' sample policy, maybe we'll try. The entire project has been heavily employing samples anyway... 🙂
Gapped or those others, umm, theoretically yes right away!, except - where can you get them at <20 pieces per order and off the shelf (i.e. not custom design). I know only Muuntosähkö / www.Trafox.fi around here in Finland that is willing to sell ferrite components for non-corporate customers, but they have a minimum order and the stuff gets quite expensive for gapped. I was and am going for Txxx-2 etc since the local Suomen Radioamatööritarvike has them. They also have ferrites but they're mainly low power and for radio amateur RF works. Places like RS, Farnell, Mouser, just totally suck at anything even remotely magnetic and >1W.
hmm, Mzzj would you know any other places that sell ferrite around here for "hobbyists"?
Genomerics: your air gap calculation looks deceptively simple... there's probably a bug somewhere ;-) Inductance depends on air gap size, and most field energy is stored in the air gap so I'd think one would start the calcs from the max energy (which however depends on inductance also, so this is an iterative mess..?). IIRC there's also a chapter on this in Abraham Pressmans book. I've never bothered to calculate these, it just makes your head hurt
IMHO it's simpler to slap on the minimum number of turns, then pull apart core halves by what looks "ok" and put paper or teflon sheet or whatever in between, then check the inductance and add more turns if necessary, and test the whole thing, and if it works fine, just copy the design. 😀 wrenchone: there were some Micrometals charts about (unless I misinterpreted them) core detoriation, at my specs apparently well above 100k hours of use before core goes exponential. Good to know about Micrometals' sample policy, maybe we'll try. The entire project has been heavily employing samples anyway... 🙂
jwagnerhki said:
Ahhh.... that might be because I have not worked out or given a sum that works out what the air gap should be. No sum, no calculation.
DNA
For MPP and other hi-performance materials only place that I am aware is http://www.cwsbytemark.com/mainpage_B.phpjwagnerhki said:
Even Farnell and Elfa should have ferrite cores. yeah, Farnell have ETD cores up to 59mm size and Elfa have ETD cores up to 49. ETD59 should go long way over 1W 😀
And.... finally managed to extract my head and add a couple of pages to the inductor design section.
Inductors
These two look at calculating the gap both without and with fringing effects. There is a model and method for working stuff out from data supplied from the manufacturer.
I won't claim it's 100% and I haven't tested it out extensively but hopefully it makes sense.
There may be more to come.....
Cheers
DNA
Inductors
These two look at calculating the gap both without and with fringing effects. There is a model and method for working stuff out from data supplied from the manufacturer.
I won't claim it's 100% and I haven't tested it out extensively but hopefully it makes sense.
There may be more to come.....
Cheers
DNA
mzzj: thanks for pointers, somehow did not see Elfa's core selection initially (just mini RF choke stuff). Nice to realize now they've "medium power" 😉 cores after all 🙂
Just let you know that at 250khz, that's the material -2 that give me best result about saturation and dissipation...Go ahead with your T200-2...It's not the cheaper but give best result!
Fredos
www.d-amp.com
Fredos
www.d-amp.com
Next page on inductors is up.....
Having 'designed' one ignoring some things this one looks at what the losses and temperature rise might be when the ignored things are included.
Silly thing is, having designed for a 30C temperature rise the sums say it is 35C.
Mind you, buyer beware!!!!!
I'm not saying it's wrong but, I was surprised.
Thermal Stuff
Cheers
DNA
Having 'designed' one ignoring some things this one looks at what the losses and temperature rise might be when the ignored things are included.
Silly thing is, having designed for a 30C temperature rise the sums say it is 35C.
Mind you, buyer beware!!!!!
I'm not saying it's wrong but, I was surprised.
Thermal Stuff
Cheers
DNA
After a bit of messing about...., to get rid of the database stuff.
I've uploaded the piece of software that works out AC and DC resistance of wires.
roundwires
Have fun
DNA
I've uploaded the piece of software that works out AC and DC resistance of wires.
roundwires
Have fun
DNA
And just to demonstrate the sort of idiot that I am I've noticed that it was giving incorrect answers.
I've fixed it....... I think only one person managed to download the wrong one....
Sheesh, here I am rubbishing NuForce and I'm messing up myself.
DNA
I've fixed it....... I think only one person managed to download the wrong one....
Sheesh, here I am rubbishing NuForce and I'm messing up myself.
DNA
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