Re: Transformer Identity - list speed

> If in your searching, you find some mathematical model for core

area

> vs watts, let us know.
>

The math for determinining the saturation and power handling of a
given core size involves knowledge of the following:

1.Frequency of operation (assumed to be either 50 or 60 HZ)
2.Type of magnetic material and the rated saturation of that material
in Gauss.
3.Cross sectional area of the core
4.Air gap in magnetic path.

In a standard laminated core power transformer the air gap is the
spacing between all of the laminations (not significant at 60HZ).

I have used a wildly speculative rough etimate if about 10 watts per
pound on a given 60HZ laminated core. A better indicator of output
handling capability is to measure the circular diameter of the wires
(not the leads) of the secondary if you can get to them. Use the
diameter to get the circular mils (area) of the wire and look it up
on a wire chart to get the wire size and then the max current
capability. Derate that for losses in the closed transformer by 20%
and you have a pretty good idea if what that winding will handle.
Transformer designers do not typically oversize the wire inside the
transformer since you are always playing a game as to how many layers
of wire do I need on a certain bobbin to get the number of turns to
get the right ratio. Even one wire size larger than needed can cause
you to have to use a bigger bobbin to get the "fill" and that will
cause you to have to use larger laminations and that will result is a
bigger, heavier and more expensive transformer.

If you kind of understand how a power transformer is designed you can
reverse engineer the process by making some observations. In the end
the best way is to measure the voltages with a true RMS meter on AC
and then load it down with a load and measure the heat rise over
time.