RE: inductor core, was Sizing capacitors

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hello Dr. R, et al.!

No, I did not coat 3/8 rod with varnish, the steel from my suppler seems to
be coated with something to resist rust. Furthermore, I believe the
agitation as the epoxy set helped to create minute, excellent insulation. My
controlled experiment had shown a 10 degree F and holding above ambient
temp. for twenty minutes into a 10 KW load. Someone requested pictures of
these and Terry posted them in a Temp dir. Has this been duplicated? The
inductance was also measured.

It seemed to me a fairly surprising large, more then I would cut, number of
these 3/8" rods symmetrically fit in a 3" tube. If memory serves right it
was fifty, but that may have been both tubes.

I defer to our math members to calculate the actual symmetrical number.

Long Streamers,
Jim Mora

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Monday, June 19, 2006 4:26 PM
To: tesla@xxxxxxxxxx
Subject: RE: Sizing capacitors

Original poster: "Terry Oxandale" <Toxandale@xxxxxxx>

I used 3/32" (different diameters are available) flux coated welding
rods inserted snuggly into a PVC tube, and then epoxied them in place
(poured epoxy into both ends). It warms up a little at 5 kva, but
worked very well for its purpose.

________________________________

From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Mon 6/19/2006 3:19 PM
To: tesla@xxxxxxxxxx
Subject: Re: Sizing capacitors



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

For a decent-size core, you could go down to Home Repot or Lowe's or
any lumberyard (or a construction site) and get some steel form
pins.  They are ~1/2" dia steel and smooth, unlike rebar and fairly
cheap.  Plenty long to rig up a control mechanism for adjustment, and
can be cut shorter easily with a hacksaw.

Nick A





 >From: "Tesla list" <tesla@xxxxxxxxxx>
 >To: tesla@xxxxxxxxxx
 >Subject: Re: Sizing capacitors
 >Date: Sun, 18 Jun 2006 14:39:42 -0600
 >
 >Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>
 >
 >
 >
 >Did you dip each rod into an insulating varnish before bundling to
 >reduce eddy currents?  If not, did the core get hot?
 >
 >This sounds like a reasonable solution to an expensive problem.  I
 >will also try it perhaps with 1/4 inch steel rods.
 >
 >Dr. Resonance

 <snipeze>