- How do we generate electricity on-board the aircraft?
The primary function of an Aircraft Electrical System is to generate, regulate, and distribute electrical power throughout the aircraft. There are several different power sources on aircraft to power the aircraft electrical systems. These power sources include:
- Engine-driven Alternating Current (AC) generators
- Auxiliary Power Units (APUs)
- External Power
- The aircraft electrical power system is used to operate the flight instruments, essential systems such as anti-icing, and passenger services such as cabin lighting. Electricity is produced in two types depending on their use:
- Direct Current (DC): Battery, Generator, Transformer-Rectifier (TR)
- Alternating Current (AC): Generator, Inverter
- Most aircraft are equipped with either a 14v or a 28v direct current electrical system.
- The electrical system is composed of numerous components which power various systems on the aircraft.
A320 Electrical System
- The electrical system of A320 consist of 3-phase 115/200v 400hz constant frequency AC system and 28v DC system.
- Normally aircraft system produces AC current which is further transformed into DC current for certain applications/users.
- Three main generators which can supply whole AC electrical network independently – 2 Eng Gen and 1 Apu Gen.
- If normal AC generators are lost, emer gen supply AC power through RAT (Ram Air Turbine)
- If all AC generators are lost then DC power is transformed into AC power through static invt using A/C main batteries (bat1/bat2).
Any one of the power sources (Apu, Eng 1, Eng2 & Ext Pwr) can supply the entire electrical network.
As no parallel connection is allowed on this A/C (split operation), we have to give priorities to the different power sources in supplying the bus bars.
Priority order for supplying A/C electrical network:
- Engine generators
- External power
- Off side generator
- A/C batteries 23amph (30 mins backup)