JIMMIE wrote:
On Apr 30, 9:02 pm, raypsi wrote:
You can calculate the voltage drop of the wire in

your secondary with
the heap of a wire table.http://www.powerstream.com/Wire_Size.htm

Hey OM:

That link to that table is ok. I learned building my own
transformers. Heat is the killer of any design.

What those tables don't tell you is the resistance increase caused by
heat which turns out to be run away in cases. It's like the
resistance goes up because of heat and this creates more heat
increasing the resistance further.

Leave a fudge factor in there, use the largest size wire possible

73 OM
de n8zu.

Im thinking 20 gauge enameled wire mostly because I think I have a
1000 ft roll in the attic. Not at all sure how well that is going to
fit on the core. I really want to get away from the voltage doubler in
favor of a bridge rectifier so I want to wind it for 1100 volts.

Jimmie

You really need to do some math before you start winding wire onto your
variac core. Read the theory and do some practice exercises from the info
on these web pages:
http://how-to.wikia.com/wiki/How_to_...er_or_inductor and
http://www.howyoubuildit.com/transformer/

You have a finite winding area in the center of your toroid. Wire size will
define how many turns you can get into that winding area. You might find
that AWG 20 is way too big for the secondary voltage you want.

Cheers,
--
David
dgminala at mediacombb dot net