Jab voltage regulator wiring

[Corby202]

Perhaps one of you electricly mined guys could enlighten me on something.
I have just started running wires on my plane and the thing that is puzzling me is the Voltage regulator wiring. Two of the wires basically go accross the battery, that I can understand but there is a third wire the wiring diagram shows going to the main buss on the dead side of the main switch, what does this wire do?? Also this wire is 18swg so the only protection this wire has is the main 15amp fuse??

Thanks
Phil

[tonyr]

What diagram?

Sticking a finger in the wind I'd guess you are perplexed by the bus voltage sensing wire that is designed to be connected at or close to battery positive.
It is the yellow wire on the regulator and monitors the regulator output.

Unfortunately there is a small current draw through that wire with it permanently connected to the battery.
It can be connected on the bus side of the battery/master switch or master contactor so that when switches are off it is disconnected from battery power.

Cheers Tony

[Corby202]

Thanks Tony, thats the one. The wiring diagram I am referring to is the wiring diagram in the Jabiru engine installation manual.
http://jabiru.net.au/eula/eula.php?u=/M ... 7_Inst.pdf

[peter anson]

You jogged my memory with your reply, Tony. A couple of years ago I had to replace the original 3-phase alternator on my engine, complete with the regulator, and I remember being confused by the fitting instructions. I checked it today, and sure enough, I had connected the voltage sensor directly to the battery. I checked the current leak and it's only 5.6mA, which I guess is why the error has never been obvious. I once had my car battery killed by the LED clock display when I left it for two weeks in an airport car park, but that was drawing 50mA.

Peter Anson
Sonex 894
211 hours (165 of those with the regulator incorrectly wired)