> When you say to the transformer maker
> "ICAS 50% duty cycle with maximum load period 5 minutes"
> how does he translate this to core and wire size?
> Also, how does this translate into the advertised specs for the amp.
Amplifier manufacturers just make up specs, since there are no
ICAS standards. For example, Amp Supply sold a 22 pound
1.1kVa core as a 4 kW transformer.
The best thing you can do is ask the weight and type of
transformer. If it is a good E-I lamination type, it would be about
20% or so heavier than a Hypersil-type core for equal performance.
You are reasonably safe simply comparing weight, as long as the
transformers have similar core materials. Also ask the voltage no
load and full load, and compare the percentage of sag. That is an
indicator of how tightly they pack the window with copper. If you
look at the transformer and see a big air gap in the window
between the windings and the core, you can bet the transformer is
not nearly as good as it could be for a given weight. They either
should fill that area by using extra copper or extra insulation, and
not waste the room.
73, Tom W8JI
w8ji@contesting.com
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