Lionel #50 gang car problem

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  • Member since
    October 2011
  • 894 posts
Posted by TrainLarry on Sunday, November 17, 2019 8:37 PM

Most postwar motors run better in forward because the gears especially are worn in that direction. Locos that I have had ran visably slower in reverse.

If the armature is shimmed properly and stays properly mated with the gears, the engine should run fine in reverse.

Check to make sure the brushes are making good contact with the commutator segments. Replace them if worn. Clean the commutator sections, the brushes and brushplate with Naphtha to insure good electrical contact. Polish the commutator sections with a Brite-Boy or very fine emery cloth. If the commutator sections are so worn they have grooves in them, it is time to rebuild or replace it.

The symptoms sound like a bad armature, but if it were bad, it would not run at all. The gear may also be excessively worn.

 

Larry

  • Member since
    January 2012
  • 274 posts
Posted by rrswede on Sunday, November 17, 2019 9:19 PM

Thanks, Larry. 

I agree that most of the postwar motors run better and faster in forward. 

 This particular gang car looks like it has seen a lot of use over the years but it was not abused. The commutator and brushes were suprisingly clean and the plates were pretty smooth. I did give them a going over before reassembling the motor. 

I did unwind and rewind the outer field coil today and then wired the motor as it was intended to be. With one end of each field coil hooked up to a slide post, the motor runs fine in forward but when the slide is positioned for reverse, the motor functions just as it did in my testing. Mostly it runs ok, but sometimes it does not reverse (just buzzes) and sometimes it barely runs. 

I am going to find a couple more very thin shim washers and see if I can get the motor to consistently operate.

Will update on Monday.

swede

  • Member since
    January 2012
  • 274 posts
Posted by rrswede on Monday, November 18, 2019 7:35 PM

I found a couple very thin shim washers at a specialty hardware store and just placed one on the armature shaft to see if the motor would run better. Before applying power I noticed the armature shaft bearing had almost no vertical movement when the wheels were rotated in reverse. When power was applied, the motor ran in forward but slower than previously and only buzzed in reverse. Also, when running in forward, the armature and brush holders got very hot. This car may well be relegated to the parts bin.

swede

  • Member since
    October 2011
  • 894 posts
Posted by TrainLarry on Monday, November 18, 2019 10:42 PM

It sounds like the armature is bad; probably shorted. Take the armature out and using an ohmmeter on the lowest setting, check the resistance between each of the copper commutator pieces. All 3 readings should be the same, within a few tenths of an ohm. If they are not, the armature is bad. Also check the resistance of each commutator section to the metal shaft of the armature. The readings should all be infinite - an open circuit. If you get a reading, the armature is shorted and needs repair.

A bad armature can be repaired by The Motor Doctor.

 

Larry

  • Member since
    January 2012
  • 274 posts
Posted by rrswede on Tuesday, November 19, 2019 11:22 AM

Thanks, Larry.

The armature, itself checks out, plate to plate and plate to shaft, but my rewind job certainly does not look professional. By that I mean the windings rise from the ends toward the center, sort of like a little hill. I may unwind it again and rewind with new wire. For now, though, I'll set it aside and finish repairing a couple other PW locomotives. 

swede

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