Alternator Warning

[davcrab]

Hi all, just wondering if anyone can explain the workings of the alternator warning system down to circuit board component level on the 337's?
One of our aircraft has been suffering from the front alternator warning light not extinguishing. I thought it may have been the relay sticking, but I have had that bench tested, and appears to work as it should. I'm sure with all the discussions of this system on this forum there would be a few people out there who would know this system back to front!
Thanks again.
Dan

[hharney]

What model Skymaster Dan?

[davcrab]

Hi, sorry it's a T337G.
Thanks

[Dale Campbell]

Good Luck, I have had problems with the charge system and lites for 10 years. I replaced the whole system from all relays to the diodes to the circuit board to one of the alternators. With one battery and 2 alternators and dual control circuit, it is next to impossible to keep both charge lights out. I gave up with one of the lights blinking all the time.My battery stays charged and the panel lights blink as one of the charge lights blink and the ammeter jumps from 0 to slight charge all the time. Dale

[davcrab]

Thanks for your response Dale, looks like I have quite the investigation ahead of me! The front alt out light is on all the time, so at least it gives me a solid fault to chase...much better than an intermittant one! I will continue troubleshooting in the new year, but if anyone has any sugestions between now and then, I'm all ears...
Thanks again
Dan

[WebMaster]

Years ago, on the old skymaster.uk board, Gmas and Bob Cook posted quite a treatise on diagnosing the charging system. The skymaster.uk board was run by Peter Somers, who has passed away, so of course has the information. Perhaps someone has that information stored someplace.
Alternately, Peter, when he was at the fly in at Lucaya, in the Bahamas, gave quite a speech on the charging system. Perhaps someone has notes on that. I do not.

[Ernie Martin]

A small correction to Larry's post above.

Pete Somers in the UK was our chief electrical/electronic guru and he indeed passed away this year. He was always quick to answer queries like this one and was equally quick to accept my invitation to be our guest speaker at the 2007 Annual Fly-in in Lucaya, Grand Bahama Island, where he enlightened us on these topics.

But I'm reasonably certain that he is not the Peter that created and ran the original Skymaster web site, because years earlier I collaborated with him on some of the web pages (e.g., www.skymaster.org.uk/purchase.asp).

Both were named Peter, both were from the UK, but they weren't the same bloke.

That original Skymaster web site still exists and the message board archives may be found at www.skymaster.org.uk/mba.asp but while some of the archives are there (e.g., Engines), others are missing, including the Airframe messages that cover electrical/electronic issues.

Ernie


I

[stackj]

Dave

What is the A/C Serial Number?

Will the alternator light extinguish if only the front engine is running with only that alternator on line?

Is the symptom the same if you switch to the backup regulator?