rewinding Lionel armature

[Anonymous]

I thought I found the trouble with my old Lionel, the resistance from bru***o bru***o field winding was more that the resistance from bru***o armature shaft to "ground" (sorry, I think in DC terms even for an AC motor). Clearly the elecricity would prefer the path of least resistance and therefore the windings would not be energized.

I bit the bullet and unwound the armature. Sure enough large sections of the wire insulation were melted away, no doubt short circuiting to the armature & shaft & etc. I bought some 26 AWG magnet wire and rewound the thing.

Guess what? I measure less resistance from any single winding to the shaft than through the windings!

What am I doing wrong? The wire is epoxy coated magnet wire. I kept the little cardboard insulators at the top and bottom of the armature iron stack, but along the axial length of the armature the wire has plenty of opportunity to touch the iron.

Should I be wrapping the entire rotor armature with cardboard? Plastic? Electrical tape? before winding the magnet wire?

Any armature winding advice is greatly appreciated.

[webenda]

Hi d-train,

Congratulations on even trying to rewind the armature.

I used to rewind armatures when I was into slot cars. I only used the fiber insulation on the ends. The enamel on the wire keeps it from shorting to the armature.

At this point, I would unsolder the wires from the commutator and ohm out each wire and commentator segment to the shaft.. That would isolate the location of the problem. From there, continue to investigate the cause of the short.

Wayne

[Anonymous]

Is this an amature for a vertical mount diesel. If so I can measure the resistance from slot to slot for you and then all you have to do is cut 3 sections of wire that long and wind. I guess if you love doing that fine, but most of the parts People have used ones that are perfect. I am not sure of the wire gauge and you may have trouble getting it.
Let me know if you want to know resistance as I will disconect one end of the wire so I do not get the parallel resistance and let you know.
Dave.

[Anonymous]

I discovered this problem before I replaced the commutator. I just have the armature iron stack, cardboard/fiber insulator at the top and bottom, shaft, and the windings around the iron, with 6 wires sticking out (2 ends of each winding). With my cheapo multimeter I measure ~ 1.1 ohm around any single winding and ~0.8 ohm from either end of any winding to any part of the shaft or the exposed part of the iron. Less resistance through the shaft again!

[webenda]

d_train,

Start unwinding. Measure resistance from wire to shaft as you go. When you get to the short, the ohmmeter will let you know. Examine the insulation on the wire to see what the problem is.

I am really curious to know how new wire could be shorted. The fiber insulators keep the sharp edge of the armature stack from cutting through the insulation. I can't imagine what could have gone wrong.

Wayne

[webenda]

When I read my own post, I asked, “What? The ohmmeter is already telling me there is a short. I do not need to unwind the armature to find out there is a short.”

Let me rephrase the instruction so that I can understand what I was thinking...

Connect the ohmmeter to one of a pair of wires and to the shaft. Start unwinding. When the ohmmeter changes reading from a low value to infinity (or blinks if it is digital,) you know that you have just unwound the turn causing the short. Examine the insulation along the part of the wire just unwound. When you find the problem, wind that turn back on to see if there is a sharp edge or burr that coincides with the area of damaged insulation.

Wayne