Basic Electrical System of an Aircraft
Most aircraft feature a 14- or 38-volt electrical system that is comprised of various components. This blog will identify the main components of the system and their function. Alternator/Generator
To begin, the alternator or generator supply the electric current to the aircraft electrical system. Alternators also provide an electrical charge to the battery which is used to start up the engine. The battery also stores a limited amount of energy in case the main electrical system fails.
Voltage regulators control the rate of charge to the battery and stabilize the alternator or generator output.
Battery
Following from the alternator is the battery. The battery acts an alternative power source used in circumstances such as engine startup, ground power, or emergency power when the main electrical system is down. Batteries have a limited supply of power in relation to the alternator or generator that supplies it. The type of battery is chosen with regard to its weight, cost, and charging weight amongst other factors.
Master Switch
As the name suggests, the master switch turns the entire electrical system on and off. It includes all of the electrical components such as lights, fuel gauges, and pumps. There is often an alternative switch to control the battery power. The alternator can also be cut off from the main electrical circuit via a switch.
Bus BarTo help simplify the copious amount of wiring in an aircraft, bus bars are used to connect the main electrical system to the equipment. All the equipment on the common bus bar terminal share the same voltage. In the case of a problem, bus bars help to pinpoint or isolate the problem.
Fuses and Circuit BreakersBoth of these devices are used to protect the electrical system from electrical overload. Spare fuses of the proper amperage limit should be carried in the aircraft to replace defective or blown fuses. Circuit breakers have a trip switch that is triggered to stop the electrical circuit from overloading.
AmmeterAmmeters monitor the performance of the electrical system. The ammeter is in the form of a gauge with a zero point in the center. When the pointer is on the positive side, the charging rate of the battery can be read. If the point is on the negative side, the battery is drawing more energy that is being replaced.
Ground Power UnitsThese are a separate unit to the described electrical system. Fixed GPUs provide 400Hz power from a fixed location. Mobile GPUS can deliver power to an aircraft that may be isolated. Both GPUs are used to start the electrical system in cold weather.
The electrical system on an aircraft is comprised of many different components that supply, monitor, and regulate the flow of electricity. Without the electrical system a modern aircraft would be significantly harder, is not impossible, to fly. The correct knowledge and maintenance of the various electrical components is required to ensure that the aircraft remains airworthy.
