On Tue, 26 May 2009 20:11:52 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Gunner Asch fired this volley in
:


Odd..I do it regularly.

What, at no load? Gunner, I worked for a couple of years in the
design and testing lab of Florida Transitron. I know just a bit about
them, and have made many from scrapped parts of others, since.

A 2:1 step-down transformer is NOT wound precisely to 2:1 ratio,
unless it's: 1)so lightly loaded as to constitute virtually no load at
all, or 2) working at much higher frequencies than 60Hz (and even then
loading plays a factor).

Or 3) if it's in the size range being discussed here. The turns ratio
is tweaked in smaller dry-type transformers, but is equal to the
voltage ratio in larger units. The transition point varies between
manufacturers: Acme compensates single phase xfomers below 1 kVA and 3
phase units below 15 kVA; Hammond drops the compensation at 3 and 6
kVA.

You do need to pay extra attention to the actual internal connections
in 3 phase xformers when reverse connecting.

--
Ned Simmons