[AMPS] Fw: ICAS rating confusion.

[Tom Rauch]

> 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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