David,

 

Just got done with a long and difficult trouble shooting experience of intermittent electrical problems in my Legacy.

 

First of all, the mechanic I was working with told me that Kelly alternators have a bad reputation for reliability.  Based on that, we swapped it out for a rebuilt Continental alternator.  That turned out NOT to be the problem.

 

We checked all the leads and redid the grounds thinking that might be the problem.  That turned out NOT to be the problem.

 

We found out that my dual alternator, dual bus system was cross-feeding between bus 1 and 2.  I operated on only one alternator.  That turned out NOT to be the problem. 

 

All of these “fixes” worked well for about the first 30 minutes of every flight.  However, after about 30 minutes the problem would develop again.

 

Eventually, we replaced my voltage regulator, which (as I reconstruct the problem) had probably gotten wet due to a problem with my canopy seal.  That turned out to BE the problem.

 

Good luck!

 

If you are a devotee of a primitive religion, you could consider sacrificing a goat or chicken to the electrical gods.  Who knows, it might help!  (No animals were harmed in the writing of this email)

 

D. Brunner

N241DB

 

 

This is probably a question for my mechanic, but can alternators start failing after 180 hours on IO-550’s?  Is failure typically intermittent?

 

(I am getting intermittent drop-offs in the Amps reading on my engine monitor – down to single digits and then negative amps in the teens and then the system restores to normal after 1-2 minutes.)

 

 

 

David Taylor

Lancair Legacy
dtaylor@crescentpark.com