The Aircraft Electrical System

Alternators
 
Often confused with generators, the alternators are engine-driven energy sources that generate the necessary current for the various electrically-powered aircraft systems. They operate by creating an alternating current through the rotation of a magnetic field inside a coil of wires. This highly-efficient machine is capable of producing a sufficient current to operate all aspects of the electrical system soon after the engine is turned on. Unlike generators, alternators supply a more constant output even at varying engine speeds, helping prevent over and under voltage. In order to cater to the vehicle's needs, a voltage regulator is installed on either the engine firewall or near the instrument panel.
 
Generators
 
Although very similar in operating principle to alternators, generators have the capacity to produce AC or DC energy. However, generators feature a mobile armature, causing the brushings to wear out quicker. From an economical and size standpoint, alternators outperform generators, making them the primary choice for nearly all modern aircraft.
 
Battery
 
Both the alternator and generator require the engine to be running in order to create energy. Therefore, a battery must be used to start the engine and serve as a backup energy source during periods of low generator or alternator output. It is important to note that generators tend to require higher RPMs to generate a strong enough current to power the electrical system, so aircraft not utilizing alternators are more likely to require battery input early in operations.
 
Alternator Switch
 
In the rare event of alternator failure, the pilots may disengage the system using the alternator switch. After the alternator is turned off, the plane will be running solely on limited battery power, making it necessary for the pilot to shut down all nonessential electrical equipment.
 
Bus Bar & Circuit Breakers
 
The bus bar connects the alternator, battery, or generator to all peripheral equipment. This configuration allows for separation between the distribution and receiving ends while still permitting simple wiring. Circuit breakers function similarly to the devices found in a home, protecting equipment from transient overvoltage. Although older aircraft implemented fuses to serve this purpose, most have been replaced by safer, more effective circuit breakers.
 
Ammeter
 
These monitoring devices continuously monitor the alternator or generator output as well as battery charging speed. Although many aircraft are equipped with a visible ammeter, allowing the pilot to see the actual performance value, others only display a warning light upon system malfunction.
 
Conclusion
 
When you are looking to upgrade or replace electrical system components, there is no better alternative to Aerospace Purchasing. We are an AS9120B, ISO 9001:2015, and FAA AC 00-56B accredited distributor with a ready-to-purchase inventory containing over 2 billion items. With our immense and diverse catalog, we are uniquely positioned to help customers procure the exact component they require, regardless of how obscure. Additionally, with our global network of distribution centers, we are able to offer around-the-clock expedited shipping to both domestic and international customers. To get started on the purchasing process today, simply submit an Instant RFQ form through our website, and one of our account managers will reach out to you with a customized solution within 15 minutes or less.