Dear All
i have a couple of final questions about the generator/alternator used on trainers which might help to dissipate my doubts once for all, .....
while if i understand it correctly, the stator consisting of the 3 coils spaced 120° apart and built around the rotor driven by the engine is the one supplying the AC! emf which is induced as the trickle charge is supplied to the rotating armature aka field coil, through the slip rings/brush assembly, generating an electromagnetic field and in which the same armature is spun ....
Is that a correct statement?
That's pretty good. We usually refer to the "trickle charge" as field current. The magnetic field produced is proportional to this field current and the resulting stator emf is proportional to the product of this and the velocity at which it crosses the stator windings.
The "alternator, generator" nomenclature is often used interchangeably. Old style DC generators had low current fields on their stators and took high current power off their rotor via a brush type commutator. But high current brushes are a maintenance nightmare. So the rotating field, fixed stator design was adopted from utility type AC generators once suitable solid state rectifiers became available. The name "alternator" distinguishes this design from the former brush commutated "generator" used for automotive and aircraft DC systems in the old days. On larger aircraft, the generator is still referred to as a generator, differing from an alternator only in that it directly supplies AC buses and loads (and by its capacity).
The other stuff about BAT and ALT switches I'll leave to the folks familiar with trainers and similar aircraft. These have different functions that those on the "big jets" I'm more familiar with.
