Definition
The application of a controlled current to the field windings of a generator or alternator to produce the magnetic field needed for it to generate electrical output. Without excitation, the rotating armature produces no usable electrical power.
Plain English
Feeding a small amount of electricity into a generator so it can build up the magnetic field it needs to make its own electricity.
Context Anchor
Seen in aircraft electrical system descriptions, especially when discussing generators, alternators, field circuits, and charging-system faults.
Derivation
From the Latin excitare, meaning 'to rouse' or 'to stir up.' In electrical terms, it describes 'stirring up' the magnetic field that allows the generator to start producing power.
Why Pilots Care
Proper excitation is required for the generator or alternator to charge the battery and supply power to radios, instruments, and other systems.
Intuition Check
Do not read this as ordinary excitement or emotion. In this electrical context, excitation means supplying current to create a magnetic field.
Example Sentence 1
When the field circuit breaker popped, the alternator lost excitation and stopped charging the battery.
Example Sentence 2
Without battery voltage to provide excitation, the alternator will not begin producing power.