I have a gang car that I just rebuilt with a new armature, new brush plate and brushes. The car had originally been overheated causing the old brush plate to partially melt. After the rebuild the car will barely go forward, have to crank the transformer way up, and will not go in reverse at all. When going forward, there are a lot of sparks from the track pickup and it heats right up. Everything is wired properly, but I can't for the life of me figure out what could be wrong. The only thing I can think of is that the field windings are bad, too, after the severe overheating, does this sound reasonable? Upon inspection they look fine. I've rebuilt a lot of post war engines, but this one has be stumped, any thoughts?
There is a ball bearing that sits between the top of the armature shaft and the brush plate. Check to make sure it is there. If it is missing or has been pressed too far into the brush plate, the armature will shift and cause the gears to bind. This will draw a lot of current causing you sparking and heat issues.
You may be able to get some insight into the field winding's condition by running on DC. If a chunk of it is shorted, it will act like a shorted transformer secondary winding on AC and produce a lot of heat; but on DC it's just out of the circuit and harmless, except to the extent that it reduces the number of winding turns. So, if it shows any better performance on DC, that's a clue that your field is bad.
Bob Nelson
Haven't checked the field windings yet, but I did install a new ball bearing in the brush plate. I can now easily rotate the wheels back and forth, no binding, however when I run it I still have the same trouble. Struggle in forward throwing a ton of sparks from the pickup, and in reverse it just sits and hums, no movement. Field windings are the only thing left. Let you know what I find.
You certainly may have a bad field. There is additional information on gang car repairs in this thread.
http://cs.trains.com/TRCCS/forums/t/186687.aspx
Our community is FREE to join. To participate you must either login or register for an account.
Get the Classic Toy Trains newsletter delivered to your inbox twice a month