Lionel 2343 motor stuttering

[misard]

I have a postwar Lionel 2343 and one of the motors is stuttering intermittently. 75% of the time it runs fine, but then it starts to "chatter" for a while, before running smoothly again. It has the same behavior in both forward and reverse directions. The other motor runs fine. If I had to guess what's happening, it is as if one of the three coils is intermittently losing power.

I opened it up and the commutator and brushes were pretty clean but I cleaned them again thoroughly and it didn't make any difference. The tension of the spring on the brushes is good, and there is not any visible difference in sparking between the brush and commutator when it is stuttering or not. I can't see any obvious loose wires.

Does anyone have advice on the next thing for me to try in order to diagnose the problem? I have basic tools and a basic voltage/ohmmeter, but no oscilliscope or anything fancy.

Thanks,

Michael.

[lionelsoni]

The commutator has three plates, each of which connects to two of the three windings.  All three possible pairs of plates should show nearly the same resistance.

[Michael6268]

It could be the Armature needs oil.

[Postwar Paul]

I don't have a diagram in front of me, but these postwar motors are usually grounded through the frame and wheels. The circuit runs through one brush, back through the E- unit, into the field coil, out the other side of the field coil, then grounded to the frame, wheels, and outer rails.

In a nut shell, what I'm trying to say is there may be a dirty connection from that one motor to the frame.This made my 726 rr chatter, until I figured it out.

Paul

[misard]

Thank you for the suggestion! I checked and all pairs stabilize at about 1.1/1.2ohm. One is slightly higher at 1.2/1.3ohm but I'm guessing that's within the tolerance of "nearly".

[misard]

Thanks! I don't think that is the problem because it can chatter even when I attach an alligator clip directly to the ground side of the field coil.

[misard]

Thanks for the suggestion! I added some oil, and it might have helped a bit. I'm now not getting any chatter at low voltage, but I'm still getting it at high voltage. Is that a clue for something else to look at next?

[TrainLarry]

Remove the wiring from the 'E' unit and wire the motor directly to your transformer. One lead from the transformer goes to one brush. Attach a jumper wire from the other brush to the field connection wire. The other transformer wire connects to the motor case (ground).

Power up, and the motor should run.

Reverse the wires going to the brushes, power up, and the motor should run in the opposite direction.

Try this at various voltages and observe if the motor runs smoothly or not.

 

Larry

[misard]

Thank you Larry! I tried that. In one direction the motor is consistently smooth at all voltages. In the other direction it consistently stutters. I feel like I should be able to figure out what that means is wrong, but I can't :/

[TrainLarry]

Next thing to do is to remove the motor from the truck and power it up the same as above. It should run smooth in both directions. If it does, you probably have a gearing issue.

Try swapping the motors. See if the problem follows the motor or is in the truck.

 

Larry

[misard]

The test I did was after removing the motor from the truck. I didn't remove the gear that is attached to the armature shaft, so there were two gears meshing in my test, but no wheels to turn. The gear doesn't easily come off the armature shaft but if it's worth it I can try removing it to see if it makes a difference. Is there a trick to pop it off?

[TrainLarry]

It is not necessary to remove the gears from the motor unless they are worn.

Power up the motor in question for a good while in both directions out of the truck to insure it runs properly. If it starts to falter, most likely the armature is bad.

 

Larry

[misard]

Thanks again for your help. I think it may be a bad armature so I will start looking for a replacement. It runs adequately for now but would be good to get it smooth again.

[TrainLarry]

Send your armature to The Motor Doctor. He will rebuild it for you.

 

Larry