Problem with Alt-out light/annunciator

[Pete Somers]

I have replied to Guy direct, however here is a copy for your info.

Sorry Guy been out all day.

The Skymaster alternator system is a odd, as the electrical items are
mounted in the front engine bay including the Voltage Regulators,
which leaves a long run from the VR and the busbar for the rear alternator.
Also the alternators on the IO 360 turn slow. This causes problems with the
resistance of the long run of the cables difference from front to rear
engine and the small size wire they used for the BAT and FLD wiring to the
rear.

If you set the voltage to 28.5 using the 1200 RPM they say in the manual at
max RPM you will find that the voltage is quite high.

If you compromise on this and set the volts to 27.5 at 1700 RPM you will
find the volts ok at max rpm and the system more stable.

Some of the older avionics will not like to run at anything above 28.5
volts.

The older Skymasters with the single voltage regulator are more prone to
unstable balance and voltage variation due to age and only having one
regulator controlling two alternators.

Hope this makes sense, I will post it on the web site so others can comment.
on this.

Cheers
Pete