Motor Shorts

Best to start diagnosis by ohming out the armature poles and field coil.

What is your power supply?

I just had a problematic engine that ran hot very quickly.  The issue was something that I did not expect and took a while to troubleshoot.

The problem was that the brush plates on the armature were covered in grease/grime that seemed to be burned on.  I used copper cleaner to clean the brush plates, after swapping out the armature and finding that was the problem.  So check the brush plates on the armature and clean them if necessary.

Here is a link to the post I made on the subject, with some photos of the armature brush plates.

https://ogrforum.com/...armature-overheating

NWL

Yea you have to check the armature and the stationary coil.Make sure the armature ohms out at close to the same for each segment. There is a you tube video (about Lionel motors) which are basically the same .Look up lionel motor test by Shamus.

also the armature 3 segments can have groves worn into the copper this happens if the brushes wear down to much and either by the brush cocking or the springs contact the commutator ! always change the springs and brushes when repairing the motor and polish commutator with fine polishing cloth or very fine emery paper/ copper should look like a mirror after being polished !

actually also the field winding or armature winding cook be cooked from overheating look at the actual winding for dark color the winding should be bright color not dark!

Alan

One more thing to check.I recently had a motor running very hot. I found that the previous owner had unwound about 4 loops from the stationary coil and used that.(I guess the wire broke or something).I didn't notice it and after cleaning and replacing brushes ran it for about ten minutes. Boy did it get hot.