Download Ground Power Supply The external AC ground supply receptacle is

Ground Power Supply
The external AC ground supply receptacle is accessible directly from the ground and outside the
hazardous suction area of the engine air intakes.
The ground supply receptacle is located so as to minimize the possibility of damage by normal
ground servicing equipment.
The external AC ground supply receptacle has a capacity of 90KVA.
The external power is controlled from the flight compartment and can be energized with or
without the main aircraft battery. The external power either supplies automatically all the busbars
by means of the EXT PWR pushbutton switch or separately supplies the ground service busbar.
An amber warning light and a white indicator Light are located near the external ground
receptacle. The amber warning Light indicates that the external power is available.
The white indicator light indicates that the power supply is not in use.
The external power pushbutton switch indicates if the external power is available and if it is in
use.
A provision is made to support the weight of the cable outside the aircraft.
A power system isolation protection is provided to prevent damage to 28 volt DC control system
in case of alternating current system failure.
Normal Electrical Loads on the Ground
In ground configuration, in addition to the power necessary to the maintenance all the circuits,
except those which are connected to the engines, are supplied as in flight.
In these conditions, the maximum power on the ground is approximately 75 KVA ; this value
does not take into account the supply of the galleys, which according to the aircraft interior
layout, may reach 60 KVA.
This power is distributed as follows
115/200 V, 3-phase AC normal busbar 1 : 18 KVA
115/200 V, 3-phase AC normal busbar 2 : 38_9 KVA
115/200 V, 3-phase AC essential busbar 3 : 6_5 KVA
28 V DC
: 11.6 KVA
Galley supply sources are busbar 1 with 35 KVA and busbar 2 with 25 KVA.
The electrical power can be provided either by a ground power unit (GPU) or the APU.
When both sources are available simultaneously, the ground power unit has a priority to
electrically supply the aircraft.
A partial supply of the aircraft enabling the energization of the lighting circuits, electrical
connectors, cargo Loading and refueling circuits, can be obtained with no operation in the flight
compartment.
Ground Handling Equipment
Ground connector AN 3114-1B enables GPU type ISO 1 or ISO 2 to be used. The GPUs utilized
is featured as follows:
A voltage regulation of 115 V ± 3 V, a frequency regulation of 400 Hz ± 1 % with a harmonic
rate lower than 3% and a response time lower than 200 ms.