Aircraft slave cable pinout?

[patracy]

Anyone know what pins do what on a airforce slave connector? It's a three pin setup. Two are large and one small pin.

 

[ProviderDriver]

If you are referring to the ground power unit plug used on aircraft, the two large pins are the positive and negative terminals, and the third is just an alignment pin on most applications, on a few it does double duty as a static grounding pin. The plug I am talking about is about 4 inches on the long dimension, and about 1 inches give or take on the small axis and about 8 inches from the plug end to the cable end...

 

[patracy]

It's not the best pic, but here's the connector I'm wondering about. You can see the two large pins, but the smaller third pin is hidden from view. Can anyone tell me what pins do what?

http://apex-inc.biz/AN2552-3APLUG.JPG

 

[M35Brown]

Start on the small pin side.

The small pin is Positive
The large pin beside it is Positive
The large pin beside it is Negitive.

Note: The small pin is hot, and is used to open the GPU relay, from the GPU plug to the battery.

 

[ProviderDriver]

Yes, that is a industry standard GPU or Ground Power Unit plug. The civilian and military have them on **** near everything. The Twin Otter I flew had one installed that we used for EVERY engine start and repetedly drew well over 1500 amps momentary and 400 amps constant load at 28Vdc. There should be markings on the back of the recepticle and down inside the unit that will lable the two large pins with a + and a -, the small pin is for indexing the plug and occasional static grounding, or to carry a signal voltage to open or close relay switches on some aircraft.