Repeated Motor Over Peak Current alert

[ON28]

Update: After running the loco without the KA for about 20 minutes today, it crapped out again with a Motor Over Voltage alert. I disassembled the loco, and bench-tested the motor with my multimeter, finding a draw of more than 700mah, as per the module reading. The stall current was nearly 1 amp. Also, the motor got overly warm in less than a minute under power.

I disassembled the motor. There wasn't a lot of carbon buildup. I didn't see any obvious stray winding wires. The magnets seemed strong. The commutator was fairly clean. I removed the brushes and cleaned them with a q-tip and IPA. As I was trying to reseat one brush with a tweezer, IT BROKE IN HALF. I have never heard of this happening, but maybe deterioration of the brushes was causing excessive current draw? Could the brush springs have been too weak to begin with? Anyway, I'll be looking for replacement brushes or, more likely, an entire motor. I've got a trio of Atlas/Kato GP7s and maybe get a donor motor there.

[Alan]

I suspected such. That's why my first question to you was is the motor hot? Find a nice place in the backyard to bury the motor. It is in the final throws of dying from old age. Get a new motor.

[ON28]

I'm no motor savant, but it looked to be in excellent condition, no damage, magnets still strong, windings intact. Thought new brushes. I only paid $60 for the custom-painted loco. Still, only $20 for a new motor so yes, replacement indicated.

[Alan]

I suspect the insulation on the windings is failing. Explains the heat and the rising amperage measurements. The insulation is a varnish that gets brittle and cracks when it is old.

[ON28]

Thanks for that explanation. I have a sister unit about the same age I haven't RP'ed yet.