Where to get ferrite cores

I have a couple of things in mind and I would like a source for those BIG t= oroidal ferrite cores. I can deal with painting the wire and wrapping it be= cause you don't need that many turns. Really I can strip some 10 guage or s= omething, maybe even fatter.=20

This of course yields what the problem is _ I want like an ID of AT LEAST a= n inch, a thickness of =BC inch or better which gives an OD of 1=BD". The h= eight should be approximately =BD - =BE inch.=20

J
Reply to
jurb6006
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toroidal ferrite cores. I can deal with painting the wire and wrapping it because you don't need that many turns. Really I can strip some 10 guage or something, maybe even fatter.

inch, a thickness of ¼ inch or better which gives an OD of 1½". The height should be approximately ½ - ¾ inch.

It's not nearly that simple. Toroids come in a wide range of permeability, saturation characteristics and frequency ranges. Here's a place to start

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Reply to
mike

toroidal ferrite cores. I can deal with painting the wire and wrapping it because you don't need that many turns. Really I can strip some 10 guage or something, maybe even fatter.

inch, a thickness of ¼ inch or better which gives an OD of 1½". The height should be approximately ½ - ¾ inch.

Make sure that what you need is ferrite material. Ferrite toroids, ungapped, have pretty limited use - in pulse transformers, common-mode chokes, other EMC or damping functions and some saturable circuits.

Ferrite has more applications with other core shapes, where a gap is more easily permitted.

For most power applications, you'll need a gap of some sort, or another type of composite material that provides this characteristic in a physically cut or distributed form - iron dust, MPP/sendust or others. The descriptions of the latter can be found on Magnetic Inc, Micrometals and other websites.

The odd iron dust toroidal core size shows up on E-Bay regularly, in non-auction type sales. Core material can be identified in the part's type number, and sometimes in the body colour code. Ferrites as well.

What are you building?

RL

Reply to
legg

Thje DC to DC convertor must be extremely high current because I want it to= run off batteries. It has to kick the voltage up.=20

The reason I need my own desgn it because using high speed switching device= s, I intend to eliminate the rectifiers and filter caps. I intend to use th= e high frequency AC directly.=20

I really should not say anymore right now. If I find what I need, get one g= oing and file for a provisional patent, I will tell you all about it. I KNO= W it can be used for industial applications already, but I want to to to us= e for another purpose. That is something I will not reveal until I at least= have the provisional. It might not be enforcable, but it sure as hell prov= es prior art. At that point nobody can keep ME from marketing it.=20

(you should see what drug companies do, and Monsanto, they use patent laws = in ways that would blow you mind)

J
Reply to
jurb6006

run off batteries. It has to kick the voltage up.

I intend to eliminate the rectifiers and filter caps. I intend to use the high frequency AC directly.

going and file for a provisional patent, I will tell you all about it. I KNOW it can be used for industrial applications already, but I want to to to use for another purpose. That is something I will not reveal until I at least have the provisional. It might not be enforcable, but it sure as hell proves prior art. At that point nobody can keep ME from marketing it.

ways that would blow you mind)

Ok, so, What is your input voltage? What is your output voltage? What current do you need on the output? What frequency do you want the AC?

Answer those and we will have a better handle on how to pick your core.

Mikek

Reply to
amdx

Have you tried RS Components or Farnell?

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phycomp
Reply to
phycomp

I need to be around 60 - 100 Khz. There will be no active feeback loop, no regulation just brute force. Primary impedance will be so low that any spikes in the load will be immediately reflected to the source. It will run at resonance.

Square or sine, or something within reason at a constant frequency, able to deliver say 200 V P-P at eight amps or so.

Actually 75 Khz would probably be optimum.

J
Reply to
jurb6006

regulation just brute force. Primary impedance will be so low that any spikes in the load will be immediately reflected to the source. It will run at resonance.

deliver say 200 V P-P at eight amps or so.

In order to run resonant, you'll need some kind of control to sync the driver to the power transfer frequency. Self-oscillators tend to be supply volage dependent, and the resonant frequency of the power components will drift, all by themselves, with temperature.

Resonant converters tend to run intentionally above or below resonance, FMing into the resonance to increase/regulate power. Ungapped ferrite is unsuited to this application. Pick a ferrite core shape that allows for introduction of a gap, or use a powdered core material of suitable mix permeability and loss density for the application.

You have to determine what you need, before you can go looking for it.

RL

Reply to
legg

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