Hello I’m new to the forum and have a question. I have a early model 302 that will only run forward. I know the reverse unit is good and i have also tried the reverse unit from my 325ac and it gives the same problem with both units. Runs great in foward has new brushes as well. Wiring tests good. Now when it goes in reverse it just turns a tiny bit then heats up. Doesn’t have any binding I can turn it by hand easy. Any help would be great. Thank you.
[#welcome] aboard! I’m no good with reverse units, but there are a lot of people on here who are! [:D]
Becky
Look for a short circuit in the locomotive between one of the wires to a motor brush and one of the wires to the motor field winding. There are several ways that such a connection can duplicate a correct reversing-unit connection in one direction, but shunt current around the armature or the field when you try to run the other way and prevent the motor from running.
Your problem description states the motor heats up when it tries to reverse. If your 302 has a flat and not a drum style commutator a likely cause is the commutator is shorting against the ends of the brass brush tubes. This can be a problem with Gilbert steam engine motors. Take off the bakelite brush holder assembly and add a thin washer to the shaft, then reassemble. There may already be a washer on the worm gear end of the commutator shaft. If so that can be moved to the other end of the shaft to see if it fixes the problem.
Thank you for the help. I’ll give it a try and keep testing.
Found the problem the previous owner wired it like a 5 wire setup. Changed the two that were out of place and it runs great.