Re: Self-built power transformer (some design parameters)

To: tesla-at-pupman-dot-com
Subject: Re: Self-built power transformer (some design parameters)
From: Ed Phillips <evp-at-pacbell-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Tue, 06 Oct 1998 20:11:25 -0600
Approved: terryf-at-verinet-dot-com

"
 Hi Reinhard, all:

First, as I said, the info I presented was taken from "The Radio
Amateurs
Handbook", so your comments are directed at the authors, not me;-) 
The edition I grabbed first was a bit old (1950) so I looked at a later
version and their recommendations are somewhat less conservative but I
don't know if that's due to a change in philosophy or a change in the
core
materials available, or... The later editions give less detailed info on
the core.

The 1983 edition gives a 'conservative' figure of 1000 cm/A and 700 cm/A
for 'amateur' service." 

	The "authors" had it right!  The #10 wire has an area of just over
10,000 circular mils, and should thus be good for around 10 to 15 amps,
depending on your conservatism.  That's about right for a "1 kw"
transformer.  The wire area has nothing to do with the saturation flux
density of the core, which is the one parameter which must be attended
to with great care.  Too few turns for a given core area is much worse
than a little extra winding resistance.  House wire is rated for higher
current because it has more cooling, even in a conduit.

Ed