Aztec F 1976 exasperating Alternator inop light on

[Dlcmdrx2]

Hi guys, so after 4 months of annual+avionics we got the Aztec.

There have been always a few problems with the plane that still arent fixed. One of them is the right alternator light inop being on.

Weve change alternators twice and after my mechanic called someone about the problem, the voltage regulator was suggested.

That was changed and after 4 hours of flight the light is on again.

Symptons are:

Ground: Normal, no light at 1000 rpm. When advancing the throttle light comes on. The avionics shop suggested balancing, my mechanic did that and still didnt fix it, he then change the voltage regulator, we flew for 4 hours after that and then the light is on again.

I found this info in another forum:

On my Piper Seneca II, each alternator feeds the main bus through separate blocking diodes. (a big honking silicon diode that is the size of a half-dozen 50-cent pieces stacked up and screwed into a heat sink). The diode is actually there to protect the wiring in the event of a short. For some reason, Piper decided this was better than a breaker in the 1970's.

On the field regulation side, each has a separate field switch and breaker, over-current relay and solid state regulator. The regulators have a paralleling connection between them which serves to balance the voltage sent to the field. It is a fairly primitive system, each regulator has no idea what the alternator it controls is doing. The sense voltage is from the main bus, which is also the current source for the regulator and field.

The same Lamar regulator is also used on Beech twins with 14v electrical systems, which share a similar topology.

In practice, it isn't a really great system. It is not uncommon to have drift between the two, leading to less than optimal voltage stability and occasionally having one or the other alternators kicked off the bus.

And probably seems to be the same system as my Aztec F.
My questions are: Has anyone got a clue of how this issue can be fixed?

Can i fly with a leap of faith and if the left alternator goes inop the right alternator will be back to life?

 

[philiplane]

 

[Dlcmdrx2]