Re: Mike Marcum Ferrite Cores

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Nick Andrews" <nicothefabulous@xxxxxxxxxxx>


Maybe you can try asking them for a sample quantity of the powder, to 
see if you want to buy a truckload later on...

> From: "Tesla list" <tesla@xxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: Re: Mike Marcum Ferrite Cores
> Date: Tue, 11 Oct 2005 18:30:30 -0600
>
> Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>
>
> Well, if you buy 'em you probably won't want to grind em up lol. 
> They're good for up to 1 MHz, tho their max sweet spot is 500 kHz. 
> So they'll probably work for what you have in mind. The down side is 
> that they have a $600 minimum order and 10-week lead time at the 
> time I ordered them late last year. They're more of a manufacturer 
> than a distributer/vendor (couldn't find one for them since they 
> sell mostly to other manufacturers). IRRC I ordered 100 pcs to reach 
> the minimum, but since sold the extras I had on ebay. I might do 
> that again at some point if I ever get the time and need more cores. 
> I could do a bulk buy similar to the cd942c20p15k caps, but probably 
> wouldn't be enough interest to reach the minimum. You might give 
> them a call and if you're lucky they might save you some work and 
> just sell you the ferrite powder before they kiln it (unless they're 
> like nst makers that refuse to sell unpotted nst's), but I'd guess 
> the $600 minimum would still apply.
>
> Mike
>
>
> ----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Tuesday, October 11, 2005 1:35 PM
> Subject: Re: Mike Marcum Ferrite Cores
>
>
> > Original poster: mecortner@xxxxxxxxxx
> > >Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>
> >
> > >You can buy a pole xmfr for the price of a large ferrite core. We
> > >sell 10 kVA, 14.4 kV/220 volt units for only $95!!
> >
> >
> > Actually D.C. I thought about that when I wound the thing
> > but as luck would have it I live quite a distance from
> > you. I'm in California, way up north near Mt Shasta and
> > shipping would be prohibitive no doubt. Actually I'm
> > seriously looking at what Terry's up to right now. You
> > know, when all this solid state stuff first started I
> > just thought it was a joke, a new/fun way to blow up
> > transistors, but the results are looking real now!
> > The newest design looks so simple that I might even
> > give it a whirl? Still for the life of Me I can't
> > figure out what that little 5uF poly cap is doing in
> > parallel with the C-drive caps's?
> >
> > ---- Matt Cortner ----
> >
> >
> > >Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>
> > >C-cores. Each one is 2.25" x 4" with a 1" square cross-section. 8 of
> > >these are being put together in a modified E with the 2x2" center the
> > >primary and the 4 secondaries on each side (can be paralleled or
> > >series'd externally to get 12.5-50kV with 370vdc in). I did it this
> > >way to minimise wire length for a given # of turns (litz is
> > >expensive) and have core gaps for built in current limiting. It's the
> > >P ferrite from Magnetics (
> > >http://www.mag-inc.com/ferrites/ferrite_e_i_u_cores.asp ). Part # is
> > >OP49925UC. Biggest non-custom core they have.
> >
> >
> > That is a pretty huge core size for sure! I know
> > from previous posts that your somewhat familiar
> > with esoteric technology so you might have an idea
> > what I'm up to. I'm also building an inverter, not
> > the solid state kind though, a rotary type with rare
> > earth magnets. I plan on driving a coil with it. What
> > I need to do is cast a special stator core configuration.
> > I plan on grinding up some ferrite cores on a wet wheel,
> > separating out the magnetic dust and mix w/ epoxy for
> > casting material. And I was curious as to what you
> > thought the suitability of the cores you have are to this
> > purpose? Also about what price did you pay per piece?
> > Thanks.
> >
> > ---- Matt Cortner ----