Sorry for resurrecting an old thread, but it is exactly an issue i want to address. I think i read through every page, and am in complete surprise that nobody else has reported my exact same issue.
A quick back story. At around 300 hours and 2 years, my plane power alternator started to fluctuate and cycle from on to off while in flight. We are talking about 100% working to 100% nothing. Voltage would go from 14.1v to battery voltage 12v to 14 to 12. These cycles got more and more frequent day by day. Field breaker is fine. After talking with PP, i sent it back. Bench testing said it was normal. hmmm???
Ok, now i have a new alternator. 2 months and 40 or so flawless hours later, the SAME thing has started happening again!!! I double checked wiring, connections, etc.
Then I realized that the issue was strongly correlated with how difficult my start-up was. If it was a longer start, then the issue was way way more likely to happen on the flight. If I had a great quick start-up, then the issue was definitely less likely to happen.
That is when i first discovered this thread. All of my starts had been with Master ON Alternator Field ON. I recently started testing starts with Master ON and Alternator Field OFF. Lo and behold, the issue is more or less gone with my so far limited testing.
I am still worried about my alternator. It still want to do more testing and try and isolate the entire field wire and maybe connector as well. However, I can't believe i am the only one to notice this so far, TWICE in a row. I cannot be THAT lucky.
Anyone else notice something like this? Maybe if everyone is made aware of this correlation, others might recognize the issue???
Thanks,
Jae