The A.P.U. ( Auxiliary Power Unit,
picture a side) is an installed engine in allonge that any sees
but all hear, when it run. This serves to give electric feeding (
through a generator that disburses three-phase alternating
current ) and pneumatic feeding; the first maids to feed the
aircraft when the principal engines ( and then the respective
generators ) is extinguished while the second source serves to
have the air conditioning in passenger cabin and air in pressure
when the pilots will have to start the main engines.
If the A.P.U. had to not work maids of a
furnished express generator from the airport service company. If
the airplane in matter had to have the engine starters that works
to air, the external generator ( G.P.U.-Ground Power Unit ) will
be not more enough for the starter of the motors, but will serve
an express air compressor which is stuck to a special attack
under the fuselage to furnish the air in necessary pressure ( 32-35
PSI ) to can start the engines.An airplane as the Boeing 767,
with two motors under the wings, it have three electrical
generators: one for each engine and the third is on the A.P.U.
The generators of all the airplanes furnish a
feeding of 115 volt to 400 Hz three-phase.
The A.P.U. ( Auxiliary Power Unit,
picture a side) is an installed engine in allonge that any sees
but all hear, when it run. This serves to give electric feeding (
through a generator that disburses three-phase alternating
current ) and pneumatic feeding; the first maids to feed the
aircraft when the principal engines ( and then the respective
generators ) is extinguished while the second source serves to
have the air conditioning in passenger cabin and air in pressure
when the pilots will have to start the main engines.