# Wiring Diagram Review AF Three Rail



## FProp (Mar 8, 2018)

So I've sketched out a wiring diagram for my pre-war American Flyer 4-6-2 Pennsylvania. Finding a reference for these pre-war engines is an exercise in futility. Could I get some experienced eyes to look this over? I've marked points of soldering with squares. 
I get power to the engine. The headlamp comes on and I can hear the electromagnet click as it tries to move the pawl and push the drum up. 
Also, I've cleaned the old "grease" off of the gear, rolled all the wheels and they are free with new drops of oil. 
The armature field has 1.5 ohms resistance between the plates (3 plates). The armature moves the drive wheels when turned by thumb. New brushes were installed. 
I rewound the field coil using 26AWG enameled copper wire after breaking off too much and saying "eff it". I got 40 feet of wire back on the coil and it measures 1.8 ohms resistance between the two ends. 
The new engine wire is 22 gage solid wire and all connections were soldered. 
A three piece section of track was scrubbed with a green pad and I only got one small spark. Wheels were cleaned.

But she won't move. The attached diagram was sketched and based on notes I took when I disassembled the engine the first time. The wire color is completely arbitrary, all my wires are black.

Thanks for the assistance.


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## T-Man (May 16, 2008)

Switch your purple and blue. 

You have a three rail system and One coil wire is grounded to the outer rail. The front right connection is connected to the other coil wire,. The center wire is attached to the top left. In order for everything to work the brushes are attached to the two center finger and rotate out changing direction.

Make sure the trucks are not insulated from the frame.


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## FProp (Mar 8, 2018)

Thanks for the response T-Man! 
I zipped to the garage after dinner and switched the 2 wires (purple and blue). I rolled the armature a few times for good luck and took the reverse unit out of neutral. 

The headlamp came on but nothing else. Well, until the armature started giving off a little smoke, and got hot. 

I manually moved the drum to the neutral position and gave it some juice again. Light, but nothing else. 

I manually moved the drum to the next position (the drum is a little tight, but that's for another part of the project) and the transformer "tripped". It cut out. 

I think I may have shorted the armature. That will be a check for tomorrow. 1.3 ohms between plates without brushes touching, right?

Time to put the kids to bed.


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## FProp (Mar 8, 2018)

T-Man, 
Unsure why my previous response to your post didn't show up, but here is the result of your suggestion. 
Drum position 1, headlamp came on, no movement.
Drum position 2, headlamp came on, no movement. (neutral, so shouldn't be)
Drum position 3, transformer (lionel with safety) kicks out. 

I'm thinking (guessing) that there is a short in the system, but does it seem odd that the short would only happen in one direction?

To try to isolate the short, I first inserted a different armature coil and got the same result. Then I inserted a different field coil and got the same result. I don't have another reverse unit to plug in. I did push on all the fingers and they're making good contact. 
I pulled the center rail pick up plate from the bottom thinking that the short could be in there with the soldered connection making contact with the frame, but no. 
I checked for resistance between the center rail pick up and the wheels and it was 0.01. Shouldn't there be some resistance there if the current has to pass through the coils before exiting the wheels?
Thoughts?
Thanks.
Fred


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## T-Man (May 16, 2008)

Your last two post got caught by the filter. You need to make 10 posts.

Well I can see the posts but no one else can.

For now I cannot figure out how to release them.

However you do have an interesting problem.

That center roller has to be isolated. from the frame
Picture as shown has the center rail power on the left side of drum
.
Right side ( farthest finger ) goes to the coil. Then the other side of the coil goes to the outer rails or frame.

The two center finger shift connection between the two brushes,
That is how you change direction,.

You can disconnect from the reverse unit to test the motor.

Use a jumper to a brush and coil wire. then using then transformer connect the other two wires ( unused brush and coil .to the transformer

Current path transformer to brush to other brush to coil to other coil wire to transformer. That will test you motor.


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## T-Man (May 16, 2008)

Ok I restored the lost posting.

Sorry for the delay but with two filtered posts the thread moved on.


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