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Aircraft general knowledge
8.6.3.3 Alternating current generator
Here you can see a 3-phase alternating
current generator, which is the type most
often used in our small single-engine aircraft.
The voltage is rectified via diodes to direct
current.
If the magnetic field is created by coils, battery voltage is required for the
generator to work.
When the engine is running, the generator
supplies power to the electrical system and to
charge the battery.
8.6.3.4 Dynamo
In the dynamo there is a commutator instead of slip rings, as in the alternator.
A dynamo supplies direct current, which is tapped with carbon brushes on the
commutator, and a direct voltage is obtained without having to use diodes.
When a permanent magnet is used, a battery is not required for the dynamo to
work.
8.6.3.5 Summary
Today, alternating current generators are installed in most aircraft. They
produce better at low speeds and are simpler in construction.
A magnetizing voltage must be applied to get a generator without a permanent
magnet to produce voltage. If the aircraft's battery is completely flat (without
charge), it is therefore not worth it to hand-start it, because without voltage for
magnetizing, nothing comes from the generator.
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Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 716
