Definition
A description of how a self-excited DC generator supplies current to its own field windings. Instead of drawing field current from an outside source such as a battery, the generator taps a portion of the current produced by its own armature and routes it through the field coils to maintain the magnetic field that, in turn, produces the armature output.
Plain English
The generator powers its own magnets using some of the electricity it makes. A small share of what the spinning part produces is fed back into the coils that create the magnetic field, so the generator keeps itself running once it gets started.
Context Anchor
Seen in aircraft electrical system descriptions, especially when studying DC generators, generator field circuits, and charging-system troubleshooting.
Derivation
Excitation comes from Latin excitare, meaning to rouse or stir up. In electrical terms, exciting a generator means stirring its magnetic field into action. Armature comes from Latin armatura, meaning equipment or armor; in a generator it refers to the rotating wire-wound part where current is induced.
Why Pilots Care
Knowing this configuration explains why residual magnetism is critical and why a generator may fail to produce power after being left unused or after a short circuit.
Grounding Statement
Once the generator starts turning, a small amount of its own output can be fed back into its field circuit so it can produce normal electrical power.
Intuition Check
“Field” does not mean an airport or open area here; it means the generator’s magnetic field. “Excitation” does not mean vibration or emotion; it means electrical current used to create that magnetic field.
Example Sentence 1
In a self-excited generator, the field excitation current comes directly from the armature, so the unit needs residual magnetism to begin producing power.
Example Sentence 2
Because field excitation current comes directly from the armature, loss of residual magnetism prevents the unit from building voltage.