Large Scale Central

GP9 Motor Wiring

Modeling Motive Power
#1

I have a USA Trains GP9. It was shipped to me and the trucks have been kinda destroyed. I have the truck motors but the wiring has been disconnected. Can anyone help me about the following.
If you look down at the truck motor with the 4 pins on the right side, there are two pins on the upper side and two pins on the lower side. I can assume one pair is for power pickup and one pair is for driving the motor. If that is a correct assumption, can someone tell me which two pins are for power pickup? Then the other two pins would be to drive the motor.
Or do I have this completely wrong? I’m trying to understand which wires go to which pins.

Thanks for any help anyone can give me.
Keith Johnson

#2

Your assumption is correct, but I cant remember which is which. Not hard to test with a continuity light or meter from one of the skates to a pin. Find one that is continuous; that pair of pins is the track pick-up. The other pair is motor.

Polarity will be opposite on each truck because the pins face each other when trucks are on the loco.

I have a GP9 in deep storage. If you can’t figure it out, I can dig it out and look.

#3

Jon, thanks for your input. It seems I have depended on your knowledge a lot lately. Is the skate you refer to the end that fits onto the pin? I’m assuming that. I’ll try testing for continuity and see what I can find out. (I’m a nuclear guy; this electricity stuff throws me.)
Keith

#4

image
The silver looking dohicky that is between the wheels is the skate .
image

#5

Keith the2 outside are power pickup and the 2 inside are the motor
Richard

#6

Oh, the power pickup shoes. Didn’t know they were called ‘skate’.
Thanks

1 Like
#7

Thanks, Richard,
That’s exactly what I was looking for.
Keith

#8

They and the wheel pick ups are were the power is picked up from .