HO Trains - Repairing Open Frame Motors
Mon 1-8-2024 2:11 p.m.
Recently, I bought a batch of non-working locos on ebay. I got an Aristocraft 4-4-2 up and running for 10 seconds. Then the commutator broke into 3 pieces. I put it back in the box and was down in the dumps. Last night, I pulled out the motor and worked on the 5-segment commutator. I cleaned all the pieces and glued them back on to the armature shaft. The spacing between the segments was not very uniform. I used a jeweler's file to make the segments cylindrical. Then I wrapped sewing thread and super glue around both ends of the commutator. This was followed by soldering the windings back on to the segments. A test run showed that the motor was working. I proceeded to file the rectangular graphite brushes with a trapezoidal cross-section to allow the brushes to fit between the sewing thread windings. Again, the motor ran. Then suddenly, one of the graphite brushes came loose from the brass brush carrier. This afternoon, I drilled a 0.024-inch diameter hole in the graphite brush (parallel to the brush carrier surface). I fed a piece of 0.020-inch diameter telephone wire through the hole in the brush, bent the wire into in to a "u" shape, wrapped the ends around the brush carrier and soldered the wire to the brush carrier. I have never done a repair quite like this and it all worked. I have also made my own brushes out of discarded brushes from broken power tools.
I just noticed that the sewing thread winding came loose from the worm gear-end of the armature. The other sewing thread winding next to the copper windings is still intact. I will glue the sewing winding back in place and keep experimenting. Maybe I will glue a split washer in place on the end of the armature to hold the winding in place.
ag01
