This is my display layout from the first weekend of December. I was having the same problem with trains simply cutting out after 5-20 minutes of running, BUT, I was only having it on the INSIDE loop during the weekend. It's a bit hard to see in this picture, but the outside loop has a grade going up around the far end of the table bringing it through the tunnel (which turned out pretty well, if I do say so myself). The inside loop was touching the white fake-snow carpeting the whole way 'round. The trains running around the tree were ALSO touching carpet for the entire length of their run.

So, my theory is that some kind of static charge is building between the motor and the carpet as it zips around. The outside loop train got enough space/brick between itself and the carpet with every lap that no charge could build up, while the inside loop was ALWAYS close to the fabric, same as the trains around the tree. So, is it possible that theoretical charge would actually build up strong enough to cut out the motor? If not, what else could cause the engines to simply cut out? My only other theory is heavy trains overheating the motor, but this was happening even with the tank train you see on the inside loop, the lightest freight cars I have!

Wat do, 1chan?

>>131318

I'm going to guess it's a simple thermal protection in the train motor, those things are really not built to be run for long times continually, nor to pull lego trains much longer than about three cars.

Your inner loop has much tighter curves and more curved track compared to straight one and the train is longer too, so all lego cars running against flanges in curves would cause the motors to work hard enough to overheat after some time.

>>131336

My only quarrel with the overheating idea is that these motors have been running for years, and this problem has never occurred with such frequency before.

>>131336

I'd second this.

I've also heard that once they start tripping the thermistor, they're more likely to start tripping the thermistor in the future, so that would explain why you'd suddenly have a lot once the failures started happening.

>>131348
Thanks. I have no idea how small DC motors behave as they wear down. Would make sense than increased heat output would be part of it.

I did have motor control at poly, but DC motors were covered more as a side note, as in "these used to be popular before frequency converters became cheap". Did run one agains a dynamometer to see how armature field retardation affects its speed and torque.

My meager guess that all my gut feelings are completely against is the normal case, that is that the graphite debris from the brushes has clogged the commutator and causes some current to leak in it that generates enough heat increase to trip the thermistor. In school, heat in the commutator wasn't really seen as a problem, more like that it reduces torque.

>>131349

They're actually AC motors, but the idea of opening them up for another thorough cleaning isn't a bad idea.