Once upon a time, you were sitting and writing:

> The alternative method, by which every user would check its power supply at
> every sim-cycle seems wastefull, especially when you have 300+ users.  

I agree. 

> AC components can have any number of suppliers, but generally only use
> one at a time.  DC components can use all their suppliers at the same
> time.

In reality, AC sources should be matched (otherwise, 
bad things happen). Connecting one AC source is a good
idea (and easy to implement in software)

If AC steady-state analysis is implemented, I believe
we should employ some complex numbers (as those phasor 
techniques are easy to use).

As for your suggestions: if I get you right, you suggest
building an electro-mechanical model, where energy can
"flow" from/to the engines, generators, busses suppliers
etc. This looks nice, but it will take a while to implement.

> 1)  CSD  (constant speed drive), which exists between an engine and its
> generator.  The CSD has one supplier, the engine, and one user, a generator.

And so, it must incorperate with the engine model of the FDM. 
In that case, the engines should publish RPM data going to the

> 2) Battery, nominally 28 Volt, which will last about 30 minutes if it is the
> only power source available.  It is normally supplied by the battery
> charger, so if the charger is powered the battery is transparent.

Is it always 28V ? 

> 4) APU (auxilliary power unit), which could be derived from a turbine
> object, but I think that would be a waste.  It supplies 115V/400Hz
> electrics, and usually supplies pneumatics as well.  It has a Start/On/Off
> switch in the cockpit, and an EGT gauge.  It burns fuel from one of the
> airplanes main tanks.

Another turbine engine :) 
In any case, all AC sources seem to behave the same 

> on/off.  The breaker switch connects/disconnects the generator from its bus.

One generator per bus, I assume. How many bus units exist
within a typical Boeing 7x7?

> 9) Bus, a simple component which only keeps a list of suppliers and a list
> of users. AC or DC.

It also has "band limit" (so not too many units could be hooked
simultaniously to the bus). 

In any case, I love your ideas. The only thing I think should
be added is the ability to simulate current "spikes", cutoffs,
and more unwanted electrical phenomena (to make flight more interesting).

> I'll soon draw up a diagram of a typical Boeing electrical system and send
> it to whoever wants it.

That would be great. 

I still wonder why I hated electrical engineering courses back
then, and now, I really like it (if I ever teach an EE course,
I'll give it as a homework question ;) )

All the best,

    //        //
   (o)o)     (-)-) booom !
  ( ._.)    (    o)
   > <       >  <

  Elad (elady) J. Yarkoni 
  "Elady" for friends or....
  "Oh my God... - It's Him !" for fans (or turbofans).
  WWW:   http://www.ee.bgu.ac.il/~elady
  Dept. of ECE, BGU, Beer-Sheva, Israel, 84105.

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