Is my alternator going SoutH?

[rwarre]

So I had this great trip planned and all was good until my first fuel stop. When I took off my alternator showed it was producing 10-11 volts instead of the 13 that I was used to. So I turn around and made my way back to my home base hoping that I didn't loose any electronics. Now I need to trouble shoot. My plan is to check for loose wires, then take the alternator to a auto parts to have it checked out. What else should I look at?

[lr172]

Clearly your alternator wasn't producing output. My suggestions.

1) Confirm that belt is tight or not missing.
2)confirm that Alt. FIeld CB or fuse in not blown
3) confirm you didn't accidently turn off the Alt Field switch
3)Check for loose wiring at back of Alt. Visual check may not be adequate. I have seen several people discuss problems with the connector provided by a certain provider's alternators (don't remember the brand but it was a popular one). May want to use a continuity tester.
4)check Alt output fuse, if you have one (blown fuse means you need to closely checking wiring for short and/or alt is also likely shot)

Do you have an external voltage regulator? If so, you can manually apply 12 VDC to the Field. If Voltage goes up, Alt is good. You need to be careful with this, as voltage keeps going up. However, it is more likely that your alternator failed than a solid state external regulator. safer to pull the alternator and have autozone test it for free. However, if you have one of the aviation alternators, autozone may not have a plug to connect to it. I don't use one so do not know if it is a standard auto type connector.

Good luck,

Larry

[RONSIM]

I thought it was the alternator and changed it out --- still no joy! Ended up replacing the voltage regulator ---- all good!

[Aggie78]

Output terminal on my PlanePower alternator- securing nut had backed off enough to create some very erratic electrical readings inflight.

Torqued it back to spec, all was good.

Cheap to check and cheap to fix....and now it's looked at each time the lower cowl comes off.

[rwarre]

Took the alternator to the auto parts and had it checked out. Electrical system failed immediately. New one to be installed.

[Whitman]

I've had a nagging issue over the last year with mine. Two days ago, the alternator didn't come online for the short flight in the pattern. Tonight it did first flight!

10 minutes later, I shutdown and changed passengers and it didn't come online again after engine start.

I think I've troubleshot to the Master switch as I toggled the Alt half of the switch on and off 10 times and it came online again. Luckily the Cessna Master switch on ACS is only $37.50 so I may try another.

[N941WR]

I have a pullable breaker on my alternator fIeld and it had not been pulled since installation. Popping it in and out 20 or 30 times solved my problem.