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200nH 120A inductor

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Adam S

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Jul 7, 2009, 6:46:34 AM7/7/09
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I need to make 200nH 120A inductors for a post output filter in a SMPS.
The problem is space it a bit tight, and the conductor will be a 10 x
3mm copper bar. Does anyone know where to buy ferrite cores halves that
fit around flat bars.
I've seen them in equipment before. There have been ferrites blocks
glued around a copper bar with some spacer to provide a suitable
magnetic air gap.

I cannot easily change to a round conductor, otherwise I could just
passing through a several iron powder ring cores.

Adam

MooseFET

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Jul 7, 2009, 9:54:27 AM7/7/09
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If this is a filter just to remove RF, how about using mumetal formed
to go around the bus bar?


>
> Adam

Don Klipstein

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Jul 7, 2009, 6:10:50 PM7/7/09
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There may be either C cores or a combination of C cores and I cores that
can suitably encircle your flat bars. I have gotten ferrite cores by
Philips Magnetic Components (formerly Ferroxcube), distributed by Eastern
Components. Last time I needed some (a few years ago), minimum order
requirements were tolerable.

- Don Klipstein (d...@misty.com)

MooseFET

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Jul 7, 2009, 9:17:03 PM7/7/09
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On Jul 7, 3:46 am, Adam S <inva...@invalid.com> wrote:

How about ferroxcube u15/11/6 cores?

I think All Star Magnetics stocks them

Robert Baer

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Jul 7, 2009, 11:12:10 PM7/7/09
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Get miitary: Air Corps (air core); 120 amps has a tendency to
saturate any ferrite you would like to mention, unless the size
(cross-section) is huge.
Yes, there are "flat" ferrite "bars"; most i have seen were for flat
cable.
Worthless at even 12 amps..
An air gap large enough to prevent saturation at 120 amps would not
increase the inductance of a copper bar enough to be worth mentioning.

Robert Baer

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Jul 7, 2009, 11:14:27 PM7/7/09
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Mumetal is good at DC frequencies, not RF; formed around the bus bar
would make a shorted turn which would tend to decrease inductance of the
bus bar.

MooseFET

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Jul 8, 2009, 9:29:02 PM7/8/09
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I don't think it would. It has way more resistance than copper. At
RF frequencies, it would look very lossy.

Jamie

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Jul 9, 2009, 6:20:20 PM7/9/09
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MooseFET wrote:

can some one please tell me what DC frequencies are?

The above statement is confusing me a bit.


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