Ok, after reading at least 1000 times all your posts
(thanks a lot for your time!), I start to grab something...
Actually, the whole concept is quite clear: probably the best way to explain this matter is to use a metaphor.
I would explain it to my little daughter this way: look at the generator as if it were a car engine: the power we actually get is 80hp (KW).
In an ideal world, the fuel it burns would produce 100hp (KVA), but due to the heat losses (friction, cooling etc...) we loose 20hp (KVAR).
100 minus 20 = 80.
It's as simple as that.
The lost power depends on the fact that current and voltage are not perfectly on phase.
The efficiency ("power factor") seems to be 95% on the 747 classic.
This efficiency depends also on the job of the voltage regulator-GCU: the maximum allowable difference between the 3 generators is 3KVAR on the 727.
If you agree with the above, it's enough for me
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HD: on the 727 and 737 the switch can be left indifferently on the IN or RISE position.
If you put the switch according to the "all on" general direction of all switches you'll have RISE on the 727 and IN on the 737.
I was just wondering if the routine position deserves an entry in the checklist... but now I agree with you it's better to keep it in IN
to have a better general picture.
Thankyou all, standing by for your comments!