Servicing the typical 12 volt DC electric motor
At the heartbeat of any good model locomotive is the small electric motor that powers it. Most of the operational enjoyment you have (or don't have) will be directly related to this little power source. So, it is absolutely essential that it be running at its best. I've outlined the basic steps I follow when servicing the standard open-frame motors. We do several more complex operations with our servicing, but normally these basic steps will bring excellent results.
1) Carefully disassemble the locomotive, setting all of the parts in a small parts dish (this may avoid practicing what many modelers refer to as the "modeler's prayer time" on the floor). If the motor is a separate unit that mounts on the frame, as in many steam locos, then remove the screw(s) that holds the motor on. If your unit is permanently attached to the drive truck as in a diesel application, you will have to improvise these steps while following.
2) Holding the motor in your hand, spin the armature with your fingers to make sure it turns freely. Hook up a lead from your power source to the wire going to one brush of the motor, and place the other power lead to the other brush of the motor. In a standard DC application, you can normally ground the other power lead to the frame of the motor. Turn the power up and the motor should begin spinning.
3) Using a small instrument, toothpick, or other item, place a small drop of quality oil on the front and back bearing of the armature shaft. Be careful not to get oil on the windings. You should notice that the speed of the motor will increase after lubrication.
4) Carefully remove the brushes from the motor. I like to clean the brushes in alcohol, placed in a small container. Using a stiff brush, clean the brushes until all of the gummy substance is removed.
5) Next, using a Q-tip or other item dipped in alcohol, carefully clean the armature plates (where the brushes ride) to make sure any residue is removed. (sometimes I will reassemble the brushes, attach the electricity, and use a very small piece of extra-fine sandpaper to clean the spinning armature - BUT, be very careful doing this!)
6) Reassemble the brushes, hook up the electricity, and run the motor to check operation. Then, take a small piece of fine sandpaper and clean the metal of the spinning motor winding body.
7) The last thing I do prior to reassembly is repeat step #3, just to make sure both front and rear bearings are properly lubricated.
8) Assemble model and test the operation.
In most cases, this will restore the motors to smooth, powerful operation once again. If your motor is not performing correctly after these steps, you may need to replace it. Feel free to contact us with any questions you may have.
Yardbird Classic Trains