I suspect the wipers. Make sure they do not touch the axles or the trucks.
Simon
I got a multimeter today and tested continuity of wires motor wipers etc. Everything tested ok but still just sits on the track doing nothing. Its gotta be something stupid doing all this
Bruce
I would remove the wires from the motor, and check what is shorting on the frame. I assume there are wipers on the front left and rear right.
Only the right wheels should connect to the frame. If there is a reading from your rear left wheel and the frame, then there is a short from that source.
I have never installed wipers on these - make sure they are well isolated from the axles and the frames/gears.
Simon
I tested just the wheels without touching the wipers at the same time and nothing showed on the meter. Would this mean anything? When I touched the wheels and wipers at the same time I got continuity.
Explain your testing of the wheels- wheel to frame?-wheel to wheel, which ones?
You have a short so you’d expect continuity pretty much everywhere. To isolate a short internal to your locomotive needs an organized troubleshooting system.
You need to test continuity separately for each electrical path from wheel to motor contact. To do that requires that you disconnect the “other side” from the motor while you check one side.
The motor is of course always a short circuit, that’s how it works. With the motor in circuit you’ll get continuity (although the multimeter should measure a significant resistance across the motor terminals) when you test the terminals. You will get continuity if you check each side of the motor feeds while everything is connected up.
I assume you tested the axle insulation by testing for continuity across the axle from one wheel to the other wheel. All axles must isolate the left wheel from the right wheel. Open circuit.
Next test the one wheel to the frame on each axle, bypassing the trucks. One side should be open circuit while the other side should show short circuit, for all wheels on the same side. Then test from there (the wheel) to the relevant motor contact (remember the motor will show continuity internally across the contacts, you’re checking the continuity to the motor only from the pick up wheel on each side).
If you get continuity to each motor contact from each correct side wheel then you can look for the short circuit. Disconnect the motor leads and test for continuity across those disconnected leads. You should get open circuit. If you don’t then you have a short. Proceed to disconnect the motor feeds and test for open circuit across the contact points
This loco, in its stock form, is not particularly complicated from an electrical perspective. Power is picked up by the wheels, which transmit the power to the trucks. The front truck picks up power from the right wheels (when sitting in the engineer’s seat). The front left wheels are isolated in order to prevent a short. The rear truck is reversed, except for the fact that the truck is isolated by a plastic bolster. A wire is connected to the truck, and one of the motor poles. The rear left wheels are also isolated to prevent a short. A simple arrangement, with one main drawback: the limited number of wheels that pickup power. But that’s not your problem right now.
Can you confirm that the engine did not short when you first tried it? If it did not, something happened when you did the maintenance on it. Is it possible that you reversed the wheels (front in back, back in front)? What about the trucks? They should allow some movement in all directions, but should not be too loose. There are screws that hold the trucks together. Check them to see if they are holding the trucks together, but not too tightly.
Are any wires touching the frame? The wipers are something to check for sure. As mentioned previously, the wipers should only make contact with the wheels, not the axles or the trucks. Because of the metal gears, I can’t see how a wiper could work on the rear right wheels, but I’m probably missing something here.
Simon
The way this loco is set up is the wipers are on the left side wheels front and rear trucks. I did nothing to the trucks at all and from what I see I couldnt reverse the wheels as on the right side there are gears on the wheels. When I first cleaned the wipers the loco still ran for awhile then quit about and hour later. The wires look ok but I still wonder about the mystery third wire. I’ve tried touching it to the frame and also keeping it off and the loco still sits there.
Rear left wipers are probably redundant given that the motor picks up power from these wheels. But they should clear the frame.
Front left wipers might be shorting with the truck, frame or axle. Pictures might be useful.
EDIT : I assume you mean it shorts when you say it just sits there
How is power getting to the “other” pole of the motor from the right rail?
Your description indicates a previous owner added all wheel pick up to the left side. As long as the wheel wipers on the left side rib only on the insulated wheel and are wired direct to one pole of the motor then that would be correct.
Its the right rail power circuit or feed that seems likely to be an issue.
Yes, front right wheel is electrically connected to the frame. One motor pole should connect to the frame, or to the front truck. On mine, there is a tab on the truck that could be used for that purpose.
Simon
it seems the front truck is the problem. I put the loco on the track and placed a piece of paper under the wheels of the front truck and it fired up. I then did the opposite and nothing happened. I disconnected the wipers from the wheels and nothing happened. I also found that the third wire when touched to bare frame caused the motor to run and when left dangling it would not run. Any ideas going forward? Thanks
Bruce
The dangling wire should connect to the frame, as you found out. The front left wiper appears to be the culprit. Can you fix it or remove it?
Simon
I tried removing the wipers and also repositioning them and nothing happened. Wondering if the truck itself is the problem. Should I maybe put an insulating type washer between it and the frame or maybe put electrical tape in between?
Clearly the rear truck is feeding power correctly to the motor. This would be a modification of the original wiring as described.
Can you figure out how power reaches each pole of the motor from each side of the rear truck?
I am deducing from your description that there are two wires connected to one motor pole and those two wires each connect to a left side of a truck. The front truck left side wipers were connected to the rear truck left side wipers by a common wire. If so the front truck can’t be shorting or your locomotive would not run regardless of whether the front truck was touching both rails or not.
If instead one of your two wires feeds power to one motor pole from one side of the rear truck and the other wire feeds power to the other pole of the motor then yes, likely your front truck lost its insulation from the frame which round have been installed by a previous owner when converting to all wheel power pickup.
If you insulate the front truck from the frame then it should run by getting motor power only from the rear truck, assuming the loose wire is attached to the frame or directly to the “other” motor pole.
If it’s the same PFM Shay that I have, the front truck is not isolated from the frame. That’s how it picks up the power from the right rail. The front left wheels are isolated to prevent the short. The rear truck is isolated from the frame and has a wire going directly to the motor. The original motor was grounded to the frame and I assume the new (can?) motor is isolated from the frame, which is why that third (dangling) wire is necessary.
Simon
Sorry but you will need to be clear when you say “nothing happened”. Is there still a short when you removed the wipers? I suspect not. Without the wipers, you need to connect a wire from the rear truck (flip it on its back, and see the small tab on the truck - that’s where a wire should be soldered and connected to your motor). And connect the other motor pole to the frame. It should work. But now, you lost your wipers…
Simon
EDIT: if you isolate the front truck, it will not pickup power from the front right wheel. Washers are probably not going to work anyway because of those metal gears on the right side.
ill mess around with this thing this afternoon see what happens
I have gotten the thing running but it is erratic. It seems to be the rear truck this time and because it seems to lean forward and not level. The rear axel doesnt always make contact with the track. I notice that the wheels flanges are shallow for lack of a better term sand I have a difficult time getting the wheels on my code 100 track. is this typical for old brass locos? How best to get all my rear truck wheels on the track?
Bruce
Well that’s progress. The trucks hold together with screws. Remove the truck and make sure they are tight enough to hold the truck straight. Do not overtighten. I suspect this was the cause of your short through the wipers.
Simon