Alternator [NA]

[sarangan]

My car alternator failed, but the discharge light never came on. Fortunately, the battery had just enough juice to limp back home. I removed the instrument cluster, and found that the light itself was fine. It turns out that the warning light will come only if the alternator's stator winding is intact and is grounded. If the stator coil is broken, there will be no light. I was surprised that something so obvious would be overlooked by Kia motors.

 

[flyingron]

I'm surprised in this day and age a panel indicator is actually directly connected to the wiring. The one in my car is just one big computer display.

 

[Magman]

Another “ KIA challenge?”

 

[Dan Thomas]

In the legacy Cessnas, that light won't come on either if the alternator fails. (It's variously labelled as "Low Voltage or High Voltage.) It means that the regulator has failed or the ALT has been shut off, either by the ALT switch or by the overvolt sensor. Those regulators originally came from automobiles, which had a different wiring setup. Airplanes need to be able to shut the alternator off for reasons of safety. Cars don't do that.

The alternator could fall right out of the airplane and that old light won't tell you anything. The ACUs introduced later, in the 1980s, fixed that.