Definition
An electrical generator that supplies its own field current from the output it produces, rather than relying on an external power source to energize its field windings. A small amount of residual magnetism in the field poles allows the generator to start producing voltage when it begins turning; that initial output is then fed back through the field windings to build up the magnetic field and bring the generator to its full output.
Plain English
A generator that powers its own magnets using the electricity it makes, instead of needing a separate battery or power source to get started.
Context Anchor
Seen in aircraft electrical-system descriptions and maintenance troubleshooting for generator charging systems.
Derivation
‘Excite,’ from the Latin excitare, means ‘to stir up’ or ‘set in motion.’ In electrical work, ‘excitation’ refers to energizing the field windings that create the magnetic field a generator needs to produce electricity. ‘Self-excited’ simply means the generator stirs up its own field rather than depending on an outside source.
Why Pilots Care
Aircraft electrical systems rely on self-excited generators or alternators to produce power once the engine is running, eliminating the need for a separate exciter and improving reliability in flight.
Analogy
Like a campfire that uses its own heat to keep the flames going after the first spark.
Intuition Check
“Excited” does not mean emotional or simply switched on here. In this term, it means the generator’s magnetic field is being supplied with current, and “self” means that current comes from the generator’s own output.
Example Sentence 1
Most light aircraft DC generators are self-excited, drawing field current from their own output once residual magnetism starts the buildup.
Example Sentence 2
The maintenance manual requires verification that the self-excited generator reaches normal voltage within seconds of engine rotation.