Re: [CAD_CAM_EDM_DRO] Figuring transformer rating?

Tim: See my article (I will try to leave a LINK on this letter).

Two things to do: Try to "get at" the secondary wire, and "mike" it with a
"dial caliper" (or, these days, better, a Mitutoyo LCD digital! Most
wunnerful tool in my whole shop!). That'll give you the "wire-gage". Then,
look it up in a "copper wire table". If you are into math, square the
wire-dia. in mils (thousandths of an inch), and the result is "circular
mils". Figure about 750 CM per amp. 1000 CM per amp on very
conservartively-made and "cool-running" transformers.

Second: Measure the "square area" of the core (the iron INSIDE the
windings). Use a transformer-book (or the formula in my article, or the
chart) and find the "V-A rating" of this size of core. You say you HAVE the
voltage, so, divide the VA by the volts,and the result should be within 25%
of the "amp rating". Rough, but "close enough" for all but
expensive-computer- and military-work!

<A HREF="http://members.tripod.com/~schematics/xform/xformer1.htm">Roll Your
Own Power-Transformers!</A>

Jan Rowland, Troll