RE: ballast core

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Dean by way of Terry Fritz <twftesla-at-uswest-dot-net>" <deano-at-corridor-dot-net>

Hi Marc

> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Monday, April 02, 2001 11:31 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: ballast core
>
>
> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> <MShock8073-at-aol-dot-com>
>
> In a message dated 4/1/01 3:22:52 PM Eastern Daylight Time,
> tesla-at-pupman-dot-com
> writes:
>
> << One of the better variable home made inductors I have made so
> far consists
>  of an E
>  core ( 13.5" sqr area ) with 200 turns of # 10 THHN. To make the
> adjustments, I
>  slide the windings upwards ( off of the center leg) by 3/4"-1.25". This
>  increased
>  the current from 15A to 40A. Other methods include increasing
> the distance
>  between
>  the E and the I  ( increasing the air gap) for increased Amp flow. >>
>
> I know this may sound dumb, but exactly how do you measure the
> area of the
> core.

The area is the cross section of the part the coil is wound on.


 I usually think of cores as 3 dimensioned items and that indicates
> volume as opposed to area. But, I see references to square
> inches. Does that
> mean that the core is measured by height and width of the cross
> section of
> one leg (IE looking from the 'end')?
>
> Big question:
>
> How important is it to have the silicon steel from an actual
> transformer core
> to make a ballast?

You can use mild steel or soft iron. The area will have to be increased a
bit to match the silicon steel's permeability. I am sure I did not state
that correctly, but anyway there is a difference in permeability between the
materials and more core area will be required. Any good text on magnetic
circuits and/or transformer design will give enough information for the
design of a suitable core with the other materials.

 Can I make a suitable replacement by plasma
> cutting 10Ga,
> or 3/16, or 1/4 hot rolled plate iron (common sheet metal) into a
> suitable
> shape, and stacking them into a big enough cross section? If so,
> then I have
> the perfect situation. I can plug the dimensions needed into my
> CAD program,
> and use the CNC plasma cutter I have access to, and make my E's
> from scrap
> material that usually get's sold for pennies a pound to the scrap
> yard.  I
> could burn a strategically placed hole or two in the corners to use for
> bolting together the laminations or stagger some holes to use for plug
> welding, and have a handy replacement for something I can't seem to find
> elsewhere. Although It might take a while to collect up enough
> laminations
> from scrap to do the job.
>

Make me some while you are at it.


> thanks for any info,
> Marc S.
>
>
>
Later

deano