Caravan 208 STANDBY Alt Power


What is this for`?

The layman’s explanation is that it’s a standby battery in case of generator failure.

During normal operations the aircraft would power up using the main battery, providing limited power to start the engine. The engine will then run the generator, which will give power back to the main battery and the main electrical circuits. (It recharges the battery for the next start, and provides the main electrical system with its input for flight).

In case the generator would blow out (which isn’t very rare on a very powerful turbine shaft) there’s an extra, heavy “battery” attached to the system. This is the standby alternator. It too gets charged by the engine during normal operations (as batteries bleed off from cold etc.) but the moment you lose the main electrical input from the generator (it would TRIP, as the switch above it indicates), the standby alternator gives quite a powerful punch to either reset the generator in air or, if that fails, divert the aircraft on emergency power. It only provides for about 40 to 50% of the normal generator supply, but that’s enough to feed your radio’s and some instruments to get you safe on the ground again.


Very nice explanation, thanks!

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and these are they funcional what do they do?