I’m trying to install a DCC decoder in a Mantua 4-6-0 The tender wheels pick up from one rail and are connected to the motor via a wire. the Loco wheels pick up the other rail and are connected via the metal frame. I can isolate the motor from the frame but there is still a metal screw holding the motor to the frame. Anyone encounter the same problem. If so. What did you do?
Can you get a nylon screw from a hardware store?
One way to totally isolate the motor’s frame is to use a nylon screw instead of the metal one that holds the motor in place, but this should not really be necessary if you can just isolate the motor’s brush from the frame. As long as the brushes are isolated from the frame, it really doesn’t matter if the motor’s frame is touching the locomotive frame. The main thing you need to check is to perform a continuity check with a VOM between each motor brush and the locomotive frame to insure that there is total isolation of the brushes.
i’m building an MDC 2-6-0 that is similar in construction (lots of DC steam engines are) and i used double sided tape ( very thin tape , not the foam stuff) to hold the motor in place since i didn’t have any plastic screws . seems to be working very well so far but i will admit it doesn’t have any milage on it because i don’t have a layout to run it on
As long as the motor BRUSHES are isolated from the frame, don’t worry about it. Some motors have a small metal tab that connects the motor case to one of the brushes. Get rid of it. Use an ohmmeter to make sure there is no continuity between either motor brush and the frame. You do not have to isolate the motor case from the frame. Only the brushes. It’s only electrical isolation you need to worry about. Not physical isolation.
Can’t isolate the motor brushes without destroying the motor. I’ve checked hardware for nylon screws and struck out. Is anyone aware of a supplier of nylon screws preferrably in an assortment of sizes since I’m not sure what size I need other than length.
Kadee makes nylon screws for the occasion.
I have a couple 2-6-2 Mantua motors. Actually I had a third 2-8-2, one is new but in both of the others the rod holding the armature became loose and caused it so that it only ran in one direction. I heard this was a common problem. I now plan on changing the motors before converting to DCC. It did seem however, that I could isolate the poles from the motor frame easily enough withut the nylon screws.