over-voltage

edasmus · #1 11-11-08, 07:09 AM

You are welcome and thanks to everyone who has posted useful information. I have and continue to read as many as I can!

John Hoffman · #2 11-11-08, 09:37 PM

Thanks for the posts. I have a 1973 - same set up as yours. Ill check for the problem you posted. In my case some of the connections worked loose in the box to the point the avionics bus ground opened up. Fix was to just tighten up the contacts. Yours is probably tight and good to go after the work.

edasmus · #3 11-11-08, 09:44 PM

Hi John,

Have you had problems with over-voltage conditions occurring?

John Hoffman · #4 11-11-08, 09:56 PM

No over voltage in 10 yrs. now. Did have some intermittent low voltage over the years. It would show one alternator off and voltage would drop a little. That was fixed a year ago when an alternator drive failed in the rear engine. I take some credit for finding out how to adjust the voltage regulator and working with an A&P adjust it - problem is gone. I got to believe that the droping on and off due to poor voltage adjustment helped fail the alternator drive.

Dale Campbell · #5 11-19-08, 10:31 AM

Hi,
This is good information. I also have had both circuit breakers pop. In the last 100 hours I had 2 overvolage problems. One was on take off after a 2 hour flite to Lake George,NY. I push the breaker in and turned the alt. switch back on and it happened again. Of course you loose all electric power. I waited 1 minute and reset breaker and this time did not turn on alternators. Electric power came back and I flew for 30 minutes just on battery. I told ATC I had a electric problem and if I lost radio or transponder I would use a portable com I had on board. After 30 minutes they said the transponder was failing. I than turned on 1 alternator and the breaker did not pop. After 5 minutes I turned on the other and all was OK.
I told my AP and he looked and found nothing. That was a year ago. I will pull the breaker panel and look for the problem you had. Thank you, Dale Campbell

edasmus · #6 11-19-08, 05:46 PM

Hi Dale,

It sounds as if your system is somewhat different than mine. By all means I would go ahead and check behind the circuit breaker panel but for what it is worth, my problem never caused any circuit breakers to trip. The only symptom was the over-voltage sensor shutting down the alternators which is exactly what the system is designed to do. To reset the system requires turning off the alternator switches and turning off the master switch for a few seconds followed by turning the master and alternator switches back on to restore normal operation of the electrical system. Assuming no problems, the system should obviously continue to function which was not the case for me until the problem behind the circuit breaker panel was uncovered.

Good Luck.

Dale Campbell · #7 11-20-08, 08:15 AM

I did shut every thing down and wait, as you mentioned, and followed the power back up procedure. But, as soon as I put the first alternator back on, the breaker poped again. That morning when I started my flight, I had to get a battery jump to get it started. I did not fly for 6 weeks and the battery was dead. I though when it started to charge,it over charged.
Because it was 2 hours into flight before the over voltage light came on and breaker poped.
After I drained down the battery by not turning on alternators for a half hour the battery was no longer over charged and when I turned alternators back on after that all was normal again. Problem never came back, so I forgot about it. I did purchase a battery charger with maintance feature that GMAS recommended on this site and I leave that on now when not flying. It seems to work great. Dale