Maybe you could stack 3 T-400A-2 cores
Angel HB9SLV
Dan Levin wrote:
>
> Suppose that I want an inductor of 5 mH that will handle 1500 watts into a
> 3:1 SWR from 1.8 to 30 Mhz (to build an L network antenna tuner, at the
> output of a solid state amplifier, say).
>
> 12 turns on a T-400A-2 powdered iron core will give me something like 5.2 uH
> at a maximum flux density of 70 gauss at 500 volts at 1.8 Mhz (with no DC
> current flowing). 70 gauss is acceptable at 1.8 Mhz (and it gets better
> relative to the spec as you get higher in frequency). Fine, I'm a happy
> camper.
>
> Now suppose that I want an inductor of .5 mH, all else the same. 4 turns on
> the same core gets me .58 mH, close enough - but the flux density is now
> 210, well beyond acceptable limits. Things get worse for smaller inductors
> - the flux density goes through the roof for just 1 or 2 turns.
>
> I can't buy a bigger core easily - so what do I do? Is my only option an
> air core inductor (which I then have to shield...)? It seems more likely
> that I am being dense, as usual :-)
>
> Thanks!
>
> ***dan, K6IF
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|