Thanks all, you have answered my question and NOW, I know what to expect and to look for.
happy railroading.
hodaka112
I'm not sure you can really show a wiring diagram for this. As several have stated above, both the brushes must be isolated from the motor frame, which is usually grounded to the loco frame. One brush is already isolated, the other one is the problem. Most of the older style open frame motors, like Mantua/Tyco, Bowser, MDC, etc, have a brass strap connecting the motor frame to the brush spring mounting post, and there are several options for isolating it. As Chuck suggested above, put an insulating sleeve around the end of the brush spring where it presses against the brush, but make sure this sleeve is durable enough that it won't wear through easily. A more permanent solution is to cut the brass strap (using a cutoff wheel in a Dremel) somewhere over the insulated plate where the brush springs are mounted. Cut just the metal, not the insulating plate. The cut should be between the rivets holding the brass strip and insulating plate together and the metal part of the motor frame. Then put a dab of nail polish in the cut to insure insulation. After this, it's just a matter of soldering a wire to the newly disconnected brush.
If you can isolate both brushes from the motor frame, it doesn't make any difference whether or not the motor frame is isolated from the rails.
Some of my open frame motors have a wishbone spring along the top for brush tension. As installed, one leg of the wishbone was insulated and that brush had its own, separate wire. To isolate the other brush, slip a bit of insulation from a small-diameter wire over the bare leg of the wishbone. You might want to solder the brush power wire in place first, so as not to melt the new plastic.
Some of my other open-frame motors had the wire attachment 'ear' bent down and soldered to the motor frame. In those cases, break the solder joint and solder a power wire to the 'ear.'
To be certain, check with a multimeter set on 0-1000 ohms resistance. If you don't have any needle deflection with one lead on the brush and one on the motor frame, the brush is isolated and you're good to go.
Chuck (modeling Central Japan in September, 1964)
The entire motor does not need to be isolated, only the brushes. But even here, some motors were made different than others so there is no general diagram that would apply in all situations. Some of those old motors had one brush electrically connected directly to the frame, which was held to the chassis by a screw, and some had separate wires to the brushes.
If both brushes have wires feeding power to them, they should already be isolated from the frame; if only one brush has a wire running to it, one motor brush is connected to the frame internally and cannot be isolated.
I would like someone if possible to show me with a wiring diagram, how to insolate an open frame older type motor to dcc. I have some problems understanding the terminoly but a diagram would be much better.
thanks for reading and trying to help me. I have done "can" motors with noproblems.