6. DETERMINE SECONDARY TURNS. There will be a 4% to
6% loss in transformers of the size considered here. Part of this loss
is due to copper losses, and part due to magnetic losses in the iron. The
total can even vary a bit due to differences in workmanship. This loss
"goes up" as heat, usually just some warming of the transformer. All else
being equal, the %-loss is inversely proportional to the size of the transformer
in question. A good number to use for the size we are considering here
is 5%. That is, with a 5% loss, one must figure for 1.05 times the ideal
number of secondary turns given by multiplying the Secondary Voltage x
TV (TV from Step 3, above). Or,
If you have more than one secondary, you must have added the VA for each,
then used this sum for total VA in Step 1 above. Then, figure the ST count
for each, separately, using this formula each time, using the different
SV for each.
7. DETERMINE SECONDARY WIRE-SIZES. Go through the look-up
as you did in Step 5, above. Same thing.
Jan
Rowland