Hello everyone, I recently purchased a 302 AF Loco. When I first tested loco, it ran at 12 volts, 1.5 amps. I deciced to clean off old grease dirt grime ect. Lubed, greased reassembled. I did test run and much to my surprise it runs at 5 volts ,4 amps. what the heck did I do wrong and how did I mess it up????????????
Thanks
Irontooth
What condition are the brushes and springs. Did you thoroughly clean the commutator, brushes and brushplate of all oil, dirt and grease. Do the wheels turn freely with the armature out, and is there a thrust bearing at the lower end of the armature at the gear end. Did you oil both ends of the armature shaft. Is the smoke unit piston moving freely. Lastly, did you double check the wiring to the motor. Four amps probably would make the motor run hot.
Are you reading the current to the motor only, or the bulb and smoke unit also.
Unplug the 4 wire plug from the tender to the locomotive. Jump the outer 2 pins on the locomotive socket, and apply power to the inner 2 pins. That will power the motor directly, bypassing the reverse unit.
Make sure all axles are oiled and gears have grease. If everything is proper, the locomotive should not pull a bit more than 2 amps pulling 4 cars at 12 volts.
If you still get high current draw, there is a possibility of a slightly shorted armature. You need to eliminate all other possibilities first.
Here is the exploded view of the 302/302AC
Larry
Hello Larry
This is what is driving me nuts, I have done every thing you have outlined, i only have the motor and chassis, disconnected the smoke unit. the motor is powered directly from track. this motor was working fine before i decided to clean it The only thing I did was to clean it and it changed the bloody motor. Could I have cleaned the armature to create a short? How do you clean an armature?
Are the armature and field wired in parallel (wrong) or series (right)?
Bob Nelson
What did you change in the motor?
The commutator (copper sections) are best cleaned with hardware store naphtha. Some hobbyists use alcohol, but alcohol can dissolve the insulation of the armature windings, possibly causing a shorted winding. (Naphtha will not harm the windings, and can be used to clean and degrease all your trains and accessories. It will not harm paint as alcohol may, and is safe on plastics).
To check the armature, check the resistance of each commutator section to the other sections. The readings will be very low, and the 3 readings should be within a few tenths of an ohm difference between windings. Next set the ohmmeter to high ohms setting, and check each commutator winding resistance to the armature shaft. The readings should all be infinite (open circuit). Any reading at all indicates a shorted winding and is time for an armature rewind.
Here is a sketch of the wiring. Use the top sketch for 4 wire locomotives.
Hello Mr. Nelson
Thanks for the help. Senior moments live on had it hooked in parellel not series like it should be. Thanks again
Hi Larry
I used Radio Shack Tuner Cleaner on the armature, Bob Nelson showed me my mistake. I had it wired in parallel not series. Getting old can be a real pain in the armature!! Thank you again.
Glad you got the motor to run again.
I get a bout of Alzheimers myself every once in a while...
Hello Mr. Nelson,
I do have my AF 302 up and running, but then i had a thought, Is there a proper order for wiring the field and armature in series?
In principle, it doesn't matter. However, manufacturers, like AF and Lionel, have had ways that they usually wired the armature, field, pickups, frame, and reversing unit together. Even so, there are exceptions. Mostly, they tried to keep the wiring as simple as possible.
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