Steve Kraus wrote:

Jamie wrote:

what you're seeing in the xformer is normal. the xformer is
returning
the current phase from the current applied source which comes back out
of phase with it, thus, the current you see is lagging behind from
which it was created from the voltage you now see going the other
way...

Power Factor (F) is the difference between True power (resistive)
and Apparent power (reactive)...



My aim here is to estimate real power draw. I've got a switch mode supply
putting out about the same output and it draws about 8A per leg. (I don't
know anything about PF or reactive power on that one). This transformer
type rectifier is drawing 18A per leg. I know from asking around that this
particular brand is known to have inefficiently wound transformers. So
that accounts for part of it. But there's also the matter of taking into
account reactive power & power factor.

BTW, output in both cases is about 62A at about 22V.
It's possible it has a saturated core transformer. What this does is
causes the input side to exert the rated operating current at all times
but this type of design is best at keeping the transformer at a safe
operating Q to help prevent unwanted harmonics and oscillations in the
circuit that can take place where capacitors are in the coil design.
You see this in microwave ovens due to the cap in the hV circuit..
with out the saturated transformer it can hit a resonance that can
become destructive.

This isn't a problem if you plan on using the supply to it's fullest,
as far as efficiency goes..

I think what you're looking for his is efficiency measurements, not
PF..
Just load the supply to its max and measure the input side and compare
the wattage to the output side.
You will see that more energy is going to be used on the input side..